Posts Tagged ‘logs’

Set all logs to log to to physical console /dev/tty12 (tty12) on Linux

Wednesday, August 12th, 2020

tty linux-logo how to log everything to last console terminal tty12

Those who administer servers from the days of birth of Linux and who used actively GNU / Linux over the years or any other UNIX knows how practical could be to configure logging of all running services / kernel messages / errors and warnings on a physical console.

Traditionally from the days I was learning Linux basics I was shown how to do this on an old Debian Sarge 3.0 Linux without systemd and on all Linux distributions Redhat 9.0 / Calderas and Mandrakes I've used either as a home systems or for servers. I've always configured output of all messages to go to the last easy to access console /dev/tty12 (for those who never use it console switching under Linux plain text console mode is done with key combination of CTRL + ALT + F1 .. F12.

In recent times however with the introduction of systemd pretty much things changed as messages to console are not handled by /etc/inittab which was used to add and refresh physical consoles tty1, tty2 … tty7 (the default added one on Linux were usually 7), but I had to manually include more respawn lines for each console in /etc/inittab.
Nowadays as of year 2020 Linux distros /etc/inittab is no longer there being obsoleted and console print out of INPUT / OUTPUT messages are handled by systemd.
 

1. Enable Physical TTYs from TTY8 till TTY12 etc.


The number of default consoles existing in most Linux distributions I've seen is still from tty1 to tty7. Hence to add more tty consoles and be ready to be able to switch out  not only towards tty7 but towards tty12 once you're connected to the server via a remote ILO (Integrated Lights Out) / IdRAC (Dell Remote Access Controller) / IPMI / IMM (Imtegrated Management Module), you have to do it by telling systemd issuing below systemctl commands:
 

 

 # systemctl enable getty@tty8.service Created symlink /etc/systemd/system/getty.target.wants/getty@tty8.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty9.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty9.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty10.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty10.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty11.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty11.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty12.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty12.service -> /lib/systemd/system/getty@.service.


Once the TTYS tty7 to tty12 are enabled you will be able to switch to this consoles either if you have a physical LCD / CRT monitor or KVM switch connected to the machine mounted on the Rack shelf once you're in the Data Center or will be able to see it once connected remotely via the Management IP Interface (ILO) remote console.
 

2. Taking screenshot of the physical console TTY with fbcat


For example below is a screenshot of the 10th enabled tty10:

tty10-linux-screenshot-fbcat-how-to-screenshot-console

As you can in the screenshot I've used the nice tool fbcat that can be used to make a screenshot of remote console. This is very useful especially if remote access via a SSH client such as PuTTY / MobaXterm is not there but you have only a physical attached monitor access on a DCs that are under a heavy firewall that is preventing anyone to get to the system remotely. For example screenshotting the physical console in case if there is a major hardware failure occurs and you need to dump a hardware error message to a flash drive that will be used to later be handled to technicians to analyize it and exchange the broken server hardware part.

Screenshots of the CLI with fbcat is possible across most Linux distributions where as usual.

In Debian you have to first instal the tool via :
 

# apt install –yes fbcat


and on RedHats / CentOS / Fedoras

# yum install -y fbcat


Taking screenshot once tool is on the server of whatever you have printed on console is as easy as

# fbcat > tty_name.ppm


Note that you might want to convert the .ppm created picture to png with any converter such as imagemagick's convert command or if you have a GUI perhaps with GNU Image Manipulation Tool (GIMP).

3. Enabling every rsyslog handled message to log to Physical TTY12


To make everything such as errors, notices, debug, warning messages  become instantly logging towards above added new /dev/tty12.

Open /etc/rsyslog.conf and to the end of the file append below line :
 

daemon,mail.*;\
   news.=crit;news.=err;news.=notice;\
   *.=debug;*.=info;\
   *.=notice;*.=warn   /dev/tty12


To make rsyslog load its new config restart it:

 

# systemctl status rsyslog

 

 

 

rsyslog.service – System Logging Service
   Loaded: loaded (/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2020-08-10 04:09:36 EEST; 2 days ago
     Docs: man:rsyslogd(8)
           https://www.rsyslog.com/doc/
 Main PID: 671 (rsyslogd)
    Tasks: 4 (limit: 4915)
   Memory: 12.5M
   CGroup: /system.slice/rsyslog.service
           └─671 /usr/sbin/rsyslogd -n -iNONE

 

авг 12 00:00:05 pcfreak rsyslogd[671]:  [origin software="rsyslogd" swVersion="8.1901.0" x-pid="671" x-info="https://www.rsyslo
Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.

 

systemctl restart rsyslog


That's all folks navigate by pressing simultaneously CTRL + ALT + F12 to get to TTY12 or use ALT + LEFT / ALT + RIGHT ARROW (console switch commands) till you get to the console where everything should be now logged.

Enjoy and if you like this article share to tell your sysadmin friends about this nice hack  ! 🙂

 

 

 

Procedure Instructions to safe upgrade CentOS / RHEL Linux 7 Core to latest release

Thursday, February 13th, 2020

safe-upgrade-CentOS-and_Redhat_Enterprise_Linux_RHEL-7-to-latest-stable-release

Generally upgrading both RHEL and CentOS can be done straight with yum tool just we're pretty aware and mostly anyone could do the update, but it is good idea to do some
steps in advance to make backup of any old basic files that might help us to debug what is wrong in case if the Operating System fails to boot after the routine Machine OS restart
after the upgrade that is usually a good idea to make sure that machine is still bootable after the upgrade.

This procedure can be shortened or maybe extended depending on the needs of the custom case but the general framework should be useful anyways to someone that's why
I decided to post this.

Before you go lets prepare a small status script which we'll use to report status of  sysctl installed and enabled services as well as the netstat connections state and
configured IP addresses and routing on the system.

The script show_running_services_netstat_ips_route.sh to be used during our different upgrade stages:
 

# script status ###
echo "STARTED: $(date '+%Y-%m-%d_%H-%M-%S'):" | tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
systemctl list-unit-files –type=service | grep enabled
systemctl | grep ".service" | grep "running"
netstat -tulpn
netstat -r
ip a s
/sbin/route -n
echo "ENDED $(date '+%Y-%m-%d_%H-%M-%S'):" | tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
####

 

– Save the script in any file like /root/status.sh

– Make the /root/logs directoriy.
 

[root@redhat: ~ ]# mkdir /root/logs
[root@redhat: ~ ]# vim /root/status.sh
[root@redhat: ~ ]# chmod +x /root/status.sh

 

1. Get a dump of CentOS installed version release and grub-mkconfig generated os_probe

 

[root@redhat: ~ ]# cat /etc/redhat-release  > /root/logs/redhat-release-vorher-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
[root@redhat: ~ ]# cat /etc/grub.d/30_os-prober > /root/logs/grub2-efi-vorher-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

2. Clear old versionlock marked RPM packages (if there are such)

 

On servers maintained by multitude of system administrators just like the case is inside a Global Corporations and generally in the corporate world , where people do access the systems via LDAP and more than a single person
has superuser privileges. It is a good prevention measure to use yum package management  functionality to RPM based Linux distributions called  versionlock.
versionlock for those who hear it for a first time is locking the versions of the installed RPM packages so if someone by mistake or on purpose decides to do something like :

[root@redhat: ~ ]# yum install packageversion

Having the versionlock set will prevent the updated package to be installed with a different branch package version.

Also it will prevent a playful unknowing person who just wants to upgrade the system without any deep knowledge to be able to
run

[root@redhat: ~ ]# yum upgrade

update and leave the system in unbootable state, that will be only revealed during the next system reboot.

If you haven't used versionlock before and you want to use it you can do it with:

[root@redhat: ~ ]# yum install yum-plugin-versionlock

To add all the packages for compiling C code and all the interdependend packages, you can do something like:

 

[root@redhat: ~ ]# yum versionlock gcc-*

If you want to clear up the versionlock, once it is in use run:

[root@redhat: ~ ]#  yum versionlock clear
[root@redhat: ~ ]#  yum versionlock list

 

3.  Check RPC enabled / disabled

 

This step is not necessery but it is a good idea to check whether it running on the system, because sometimes after upgrade rpcbind gets automatically started after package upgrade and reboot. 
If we find it running we'll need to stop and mask the service.

 

# check if rpc enabled
[root@redhat: ~ ]# systemctl list-unit-files|grep -i rpc
var-lib-nfs-rpc_pipefs.mount                                      static
auth-rpcgss-module.service                                        static
rpc-gssd.service                                                  static
rpc-rquotad.service                                               disabled
rpc-statd-notify.service                                          static
rpc-statd.service                                                 static
rpcbind.service                                                   disabled
rpcgssd.service                                                   static
rpcidmapd.service                                                 static
rpcbind.socket                                                    disabled
rpc_pipefs.target                                                 static
rpcbind.target                                                    static

[root@redhat: ~ ]# systemctl status rpcbind.service
● rpcbind.service – RPC bind service
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.service; disabled; vendor preset: enabled)
   Active: inactive (dead)

 

[root@redhat: ~ ]# systemctl status rpcbind.socket
● rpcbind.socket – RPCbind Server Activation Socket
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.socket; disabled; vendor preset: enabled)
   Active: inactive (dead)
   Listen: /var/run/rpcbind.sock (Stream)
           0.0.0.0:111 (Stream)
           0.0.0.0:111 (Datagram)
           [::]:111 (Stream)
           [::]:111 (Datagram)

 

4. Check any previously existing downloaded / installed RPMs (check yum cache)

 

yum install package-name / yum upgrade keeps downloaded packages via its operations inside its cache directory structures in /var/cache/yum/*.
Hence it is good idea to check what were the previously installed packages and their count.

 

[root@redhat: ~ ]# cd /var/cache/yum/x86_64/;
[root@redhat: ~ ]# find . -iname '*.rpm'|wc -l

 

5. List RPM repositories set on the server

 

 [root@redhat: ~ ]# yum repolist
Loaded plugins: fastestmirror, versionlock
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
Determining fastest mirrors
repo id                                                                                 repo name                                                                                                            status
!atos-ac/7/x86_64                                                                       Atos Repository                                                                                                       3,128
!base/7/x86_64                                                                          CentOS-7 – Base                                                                                                      10,019
!cr/7/x86_64                                                                            CentOS-7 – CR                                                                                                         2,686
!epel/x86_64                                                                            Extra Packages for Enterprise Linux 7 – x86_64                                                                          165
!extras/7/x86_64                                                                        CentOS-7 – Extras                                                                                                       435
!updates/7/x86_64                                                                       CentOS-7 – Updates                                                                                                    2,500

 

This step is mandatory to make sure you're upgrading to latest packages from the right repositories for more concretics check what is inside in confs /etc/yum.repos.d/ ,  /etc/yum.conf 
 

6. Clean up any old rpm yum cache packages

 

This step is again mandatory but a good to follow just to have some more clearness on what packages is our upgrade downloading (not to mix up the old upgrades / installs with our newest one).
For documentation purposes all deleted packages list if such is to be kept under /root/logs/yumclean-install*.out file

[root@redhat: ~ ]# yum clean all |tee /root/logs/yumcleanall-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

7. List the upgradeable packages's latest repository provided versions

 

[root@redhat: ~ ]# yum check-update |tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

Then to be aware how many packages we'll be updating:

 

[root@redhat: ~ ]#  yum check-update | wc -l

 

8. Apply the actual uplisted RPM packages to be upgraded

 

[root@redhat: ~ ]# yum update |tee /root/logs/yumupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

Again output is logged to /root/logs/yumcheckupate-*.out 

 

9. Monitor downloaded packages count real time

 

To make sure yum upgrade is not in some hanging state and just get some general idea in which state of the upgrade is it e.g. Download / Pre-Update / Install  / Upgrade/ Post-Update etc.
in mean time when yum upgrade is running to monitor,  how many packages has the yum upgrade downloaded from remote RPM set repositories:

 

[root@redhat: ~ ]#  watch "ls -al /var/cache/yum/x86_64/7Server/…OS-repository…/packages/|wc -l"

 

10. Run status script to get the status again

 

[root@redhat: ~ ]# sh /root/status.sh |tee /root/logs/status-before-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

11. Add back versionlock for all RPM packs

 

Set all RPM packages installed on the RHEL / CentOS versionlock for all packages.

 

#==if needed
# yum versionlock \*

 

 

12. Get whether old software configuration is not messed up during the Package upgrade (Lookup the logs for .rpmsave and .rpmnew)

 

During the upgrade old RPM configuration is probably changed and yum did automatically save .rpmsave / .rpmnew saves of it thus it is a good idea to grep the prepared logs for any matches of this 2 strings :
 

[root@redhat: ~ ]#   grep -i ".rpm" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out
[root@redhat: ~ ]#  grep -i ".rpmsave" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out
[root@redhat: ~ ]#  grep -i ".rpmnew" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out


If above commands returns output usually it is fine if there is is .rpmnew output but, if you get grep output of .rpmsave it is a good idea to review the files compare with the original files that were .rpmsaved with the 
substituted config file and atune the differences with the changes manually made for some program functionality.

What are the .rpmsave / .rpmnew files ?
This files are coded files that got triggered by the RPM install / upgrade due to prewritten procedures on time of RPM build.

 

If a file was installed as part of a rpm, it is a config file (i.e. marked with the %config tag), you've edited the file afterwards and you now update the rpm then the new config file (from the newer rpm) will replace your old config file (i.e. become the active file).
The latter will be renamed with the .rpmsave suffix.

If a file was installed as part of a rpm, it is a noreplace-config file (i.e. marked with the %config(noreplace) tag), you've edited the file afterwards and you now update the rpm then your old config file will stay in place (i.e. stay active) and the new config file (from the newer rpm) will be copied to disk with the .rpmnew suffix.
See e.g. this table for all the details. 

In both cases you or some program has edited the config file(s) and that's why you see the .rpmsave / .rpmnew files after the upgrade because rpm will upgrade config files silently and without backup files if the local file is untouched.

After a system upgrade it is a good idea to scan your filesystem for these files and make sure that correct config files are active and maybe merge the new contents from the .rpmnew files into the production files. You can remove the .rpmsave and .rpmnew files when you're done.


If you need to get a list of all .rpmnew .rpmsave files on the server do:

[root@redhat: ~ ]#  find / -print | egrep "rpmnew$|rpmsave$

 

13. Reboot the system 

To check whether on next hang up or power outage the system will boot normally after the upgrade, reboot to test it.

 

you can :

 

[root@redhat: ~ ]#  reboot

 

either

[root@redhat: ~ ]#  shutdown -r now


or if on newer Linux with systemd in ues below systemctl reboot.target.

[root@redhat: ~ ]#  systemctl start reboot.target

 

14. Get again the system status with our status script after reboot

[root@redhat: ~ ]#  sh /root/status.sh |tee /root/logs/status-after-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

15. Clean up any versionlocks if earlier set

 

[root@redhat: ~ ]# yum versionlock clear
[root@redhat: ~ ]# yum versionlock list

 

16. Check services and logs for problems

 

After the reboot Check closely all running services on system make sure every process / listening ports and services on the system are running fine, just like before the upgrade.
If the sytem had firewall,  check whether firewall rules are not broken, e.g. some NAT is not missing or anything earlier configured to automatically start via /etc/rc.local or some other
custom scripts were run and have done what was expected. 
Go through all the logs in /var/log that are most essential /var/log/boot.log , /var/log/messages … yum.log etc. that could reveal any issues after the boot. In case if running some application server or mail server check /var/log/mail.log or whenever it is configured to log.
If the system runs apache closely check the logs /var/log/httpd/error.log or php_errors.log for any strange errors that occured due to some issues caused by the newer installed packages.
Usually most of the cases all this should be flawless but a multiple check over your work is a stake for good results.
 

No space left on device with free disk space / Why no space left on device while there is plenty of disk space on drive – Running out of Inodes

Tuesday, November 17th, 2015

no_space_left-on-device-while-there-is-disk-space-running-out-of-file-inodes-unix_linux_file_system_diagram.gif

 

On one of the servers, I'm administrating the websites started showing some Mysql database table corrup errors like:
 

 

Table './database_name/site_news_list_com' is marked as crashed and last (automatic?) repair failed

The server is using Oracle MySQL server community stable edition on Debian GNU / Linux 6.0, so I first thought during work the server crashed either due to some bug issue in MySQL or it crashed due to some PHP cron job that did something messy. Thus to solve the crashed tables, tried using mysqlcheck tool which helped pretty fine, at many times whether there were database / table corruptions. I've run the following set of mysqlcheck commands with root (superuser) in a bash shell after logging in through SSH:

:

server:~# /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–check –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log
server:~# /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf –analyze –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log
server:~# /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–auto-repair –optimize –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log
server:~# /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–optimize –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log


In order for above commands to work, I've created the /root/.my.cnf containing my root (mysql CLI) mysql username and password, e.g. file has content like below:

 

[client]
user=root
password=MySecretPassword8821238

 

Btw a good note here is its generally a good idea (if you want to have consistent mysql databases) to automatically execute via a cron job 2 times a month, I've in root cronjob the following:

 

crontab -u root -l |grep -i mysqlcheck
04 06 5,10,15,20,25,1 * * /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–check –all-databases –silent -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log 07 06 5,10,15,20,25,1 * * /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf –analyze –all-databases –silent -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log 12 06 5,10,15,20,25,1 * * /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–auto-repair –optimize –all-databases –silent -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log 17 06 5,10,15,20,25,1 * * /usr/bin/mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–optimize –all-databases –silent -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log


Strangely I got a lot of errors that some .MYI / .MYD .frm temp files, necessery for the mysql tables recovery can't be written inside /home/mysql/database_name

That was pretty weird and I thought there might be some issues with permissions, causing the inability to write, due to some bug or something so I went straight and checked /home/mysql/database_name permissions, e.g.::

 

server:/home/mysql/database_name# ls -ld soccerfame
drwx—— 2 mysql mysql 36864 Nov 17 12:00 soccerfame
server:/home/mysql/database_name# ls -al1|head -n 10
total 1979012
drwx—— 2 mysql mysql 36864 Nov 17 12:00 .
drwx—— 36 mysql mysql 4096 Nov 17 11:12 ..
-rw-rw—- 1 mysql mysql 8712 Nov 17 10:26 1_campaigns_diez.frm
-rw-rw—- 1 mysql mysql 14672 Jul 8 18:57 1_campaigns_diez.MYD
-rw-rw—- 1 mysql mysql 1024 Nov 17 11:38 1_campaigns_diez.MYI
-rw-rw—- 1 mysql mysql 8938 Nov 17 10:26 1_campaigns.frm
-rw-rw—- 1 mysql mysql 8738 Nov 17 10:26 1_campaigns_logs.frm
-rw-rw—- 1 mysql mysql 883404 Nov 16 22:01 1_campaigns_logs.MYD
-rw-rw—- 1 mysql mysql 330752 Nov 17 11:38 1_campaigns_logs.MYI


As seen from above output, all was perfect with permissions, so it should have been something else, so I decided to try to create a random file with touch command inside /home/mysql/database_name directory:

 

touch /home/mysql/database_name/somefile-to-test-writtability.txt touch: cannot touch ‘/scr1/data/somefile-to-test-writtability.txt‘: No space left on device


Then logically I thought the /home/mysql/ mounted ext4 partition got filled, because of crashed SQL database or a bug thus, checked with disk free command df whether there is enough space on server:

server:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/md1 20G 7.6G 11G 42% /
udev 10M 0 10M 0% /dev
tmpfs 13G 1.3G 12G 10% /run
tmpfs 32G 0 32G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 32G 0 32G 0% /sys/fs/cgroup
/dev/md2 256G 134G 110G 55% /home

Well that's weird? Obviously only 55% of available disk space is used and available 134G which was more than enough so I got totally puzzled why, files can't be written.

Then very logically, I thought it might be that /home directory has remounted as read only, because the SSD memory disk on server is failing and checked for errors in dmesg, i.e.:

 

server:~# dmesg|grep -i error


Also checked how exactly was partition mounted, to check whether it is (RO) read-only:

 

server:~# mount -l|grep -i /home
/dev/md2 on /home type ext4 (rw,relatime,discard,data=ordered)


Now everything become even more weirder, as obviously the disk continued to be claiming no space left on device, while in reality there was plenty of disk space.

Then after running a quick research on the internet for the no space left on device with free disk space, I've come across this great superuser.com thread which let me realize the partition run out of inodes and that's why no new file inodes could be assigned and therefore, the linux kernel is refusing to write the file on ext4 partition.

For those who haven't heard of Linux Partition Inodes here is link to Wikipedia and a quick quote:

 

In a Unix-style file system, the inode is a data structure used to represent a filesystem object, which can be one of various things including a file or a directory. Each inode stores the attributes and disk block location(s) of the filesystem object's data.[1] Filesystem object attributes may include manipulation metadata (e.g. change,[2] access, modify time), as well as owner and permission data (e.g. group-id, user-id, permissions).[3]
Directories are lists of names assigned to inodes. The directory contains an entry for itself, its parent, and each of its children.


Once I understood it is the inodes, I checked how many of them are occupied with cmd:

 

server:~# df -i /home
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/md2 17006592 17006592 0 100% /home


You see, there were 0 (zero) free file inodes on server and that was the reason for no space left on device while there was actually free disk space

To clean up (free) some inodes on partition, first thing I did is to delete all old logs which were inside /home and files I positively know not to be necessery, then to find which directories allocating most innodes used:

 

server:~# find . -xdev -type f | cut -d "/" -f 2 | sort | uniq -c | sort -n


If you're on a regular old fashined IDE Hard Drive and not SSD or you have too much files inside this command will take really long …:

Therefore a better solution might be to frist:

a) Try to find root folders with large inodes count:

for i in /home/*; do echo $i; find $i |wc -l; done
Try to find specific folders:


You should get output like:

 

/home/new_website
606692
/home/common
73
/home/pcfreak
5661
/home/hipo
33
/home/blog
13570
/home/log
123
/home/lost+found
1

b) Then once you know the directory allocating most inodes, run the command again to see the sub-directories with most files (eating) partition innodes:

 

for i in /home/webservice/*; do echo $i; find $i |wc -l; done

 

One usual large folder which could free you some nodes is the linux source headers, but in my case it was simply a lot of tiny old logs being logged on the system for few years in the past without cleaning:

After deleting the log dirs and cache folder in my case /home/new_website/{log,cache}:

server:~# rm -rf /home/new_website/log/*
server:~# rm -rf /home/new_website/cache/*

 

 

a) Then, stopping Apache webserver to check prevent Apache to use MySQl databases while running database repair and restaring MySQL:
 

server:~# /etc/init.d/apache2 stop Restarting MySQL server
..
server:~# /etc/init.d/mysql restart
..


b) And re-issuing MySQL Check / Repair / Optimize database commands:
 

 

mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–check –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log

mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf –analyze –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log

mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–auto-repair –optimize –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log

mysqlcheck –defaults-extra-file=/etc/mysql/debian.cnf \–optimize –all-databases -u root -p`grep -i password /root/.my.cnf |sed -e 's#password=##g'`>> /var/log/cronwork.log

c) And finally starting the Apache Webserver again:
 

server:~# /etc/init.d/apache2 start


Some innodse got freed up:
 

server:~# df -i /home Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/md2 17006592 16797196 209396 99% /home


And hooray by God's Grace and with help of prayers of The most Holy Theotokos (Virgin) Mary, websites started again !

Fix “FAIL – Application at context path /application-name could not be started” deployment error in Tomcat manager

Thursday, October 1st, 2015

tomcat-manager-FAIL-Application-at-context-path-application-name-could-not-be-started-fix-solution-error

While deploying an environment called "Interim" which is pretty much like a testing Java application deployed from a Java EAR (Enterprise Archive) file from within a Tomcat Manager GUI web interface after stopping the application and trying to start it, the developers come across the error:

 

FAIL – Application at context path /application-name could not be started


The error puzzled me for a while until I checked the catalina.out I've seen a number of thrown Java Eceptions errors like:

Okt 01, 2015 10:48:46 AM org.springframework.web.context.ContextLoader initWebApplicationContext

Schwerwiegend: Context initialization failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.sun.xml.ws.transport.http.servlet.SpringBinding#2' defined in ServletContex

t resource [/WEB-INF/pp-server-beans.xml]: Cannot create inner bean ‘(inner bean)’ of type [org.jvnet.jax_ws_commons.spring.SpringService] while setting bean property

'service'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#33': FactoryBean threw exception on

 object creation; nested exception is java.lang.OutOfMemoryError: PermGen space

I've googled a bit about the error:

"FAIL – Application at context path /application-name could not be started"

and come across this Stackoverflow thread and followed suggested solution to fix web.xml tag closing error but it seems there was no such error in my case, I then also tried solution suggested by this thread (e.g. adding in logging.properties) file:
 

org.apache.catalina.core.ContainerBase.[Catalina].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].handlers = java.util.logging.ConsoleHandler

unfortunately this helped neither to solve the error when it is tried to be started from tomcat manager.

After asking for help a colleague Kostadin, he pointed me to take a closer look in the error (which is a clear indication) that the reserved space is not enough (see below err):
 

java.lang.OutOfMemoryError: PermGen space

And he pointed me then to Solution (which is to modify the present tomcat setenv.sh) settings which looked like this:

# Heap size settings

export JAVA_OPTS="-Xms2048M -Xmx2048M"

 

# SSCO test page parameter

export JAVA_OPTS="$JAVA_OPTS -DTS1A_TESTSEITE_CONFIG_PATH=test-myapplication.com"

# Default garbage collector settings

export JAVA_OPTS="$JAVA_OPTS -XX:MaxPermSize=128M"

 

# Aggressive garbage collector settings.

# Do not use! For testing purposes only!

#export JAVA_OPTS="$JAVA_OPTS -Xss128k -XX:ParallelGCThreads=20 -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:SurvivorRatio=8 -XX:TargetSurvivorRatio=90 -XX:MaxTenuringThreshold=31 -XX:+AggressiveOpts -XX:MaxPermSize=128M"

 

####### DO NOT CHANGE BELOW HERE #######

# Disable X11 usage

unset DISPLAY

export JAVA_OPTS="$JAVA_OPTS -Djava.awt.headless=true"

 

# Garbage collection log settings

export JAVA_OPTS="$JAVA_OPTS -verbose:gc -XX:+PrintGCTimeStamps -XX:+PrintGCDetails -Xloggc:/web/tomcat/current/logs/gc.log -XX:-TraceClassUnloading"

 

# Enable JMX console

export JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote"

 

 

 

 

 

 

The solution is to to add following two options to export JAVA_OPTS (above options):

-XX:PermSize=512m -XX:MaxPermSize=512m


After modifications, my new line within setenv.sh looked like so:

 

JAVA_OPTS="-Xms2048M -Xmx2048M -XX:PermSize=512m -XX:MaxPermSize=512m"


Finally to make new JAVA_OPTS settings, I've restarted Tomcat with:

 

cd /web/tomcat/bin/
./shutdown.sh
sleep 5; ./startup.sh


And hooray it works fine thanks God! 🙂

StatusNet – Start your own hosted microblogging twitter like social network on Debian GNU / Linux

Monday, July 14th, 2014

build-your-own-microblogging-service-like-twitter-on-debian-linux-Status.net-logo
I like experimenting with free and open source projects providing social networking capabilities like twitter and facebook. Historically I have run my own social network with Elgg – Open Source Social Network Engine. I had a very positive impression from Elgg as a social engine as, there are plenty of plugins and one can use Elgg to run free alternative to very basic equivalent of facebook, problem with Elgg I had however is if is not all the time monitored it quickly fills up with spam and besides that I found it to be still buggy and not easy to update.
The other social network free software I heard of isBuddyPress which I recently installed with Multisite (MuSite) enabled.

Since BuddyPress is WordPress based and it supports all the nice wordpress plugins, my impression is social networking based on wordpress behaves much more stable and since there is Akismet for WordPress, the amount of spammer registrations is much lower than with Elgg.

Recently I started blogging much more actively and I realized everyday I learn and read too much interesting articles and I don't log them anywhere and thought I need a way besides twitter to keep flashy notes of what I'm doing reading, learning in a short notes. I don't want to use Twitter on purpose, because I don't want to improve twitter's site SEO with adding my own stuff on their website but I want to keep my notes on my own local hosted server.

As I didn't wanted to loose time with Complexity of Elgg anymore and wanted to try to something new and I know the open source microblogging social network (Twitter Equivalent) – identi.ca runs StatusNet – Free and Open Source Social software. StatusNet is well known under the motto of "Decentralized Twitter"

screenshot-status-net-microblogging-twitter-like-free-software-network

I took the time to grab it and install it to my home brew machine pc-freak.net. If you haven't seen StatusNet so far – you can check out demo of my installation here – registration is not freely opened because, i don't want spammers to break in, however if you want to give a try drop me a mail or comment below and I will open access for you ..

There is no native statusnet package for Debian Linux (as I'm running Debian) so to install it, I've grabbed statusnet.

To install StatusNet, everything was pretty straight forward and literally following instructionsf rom INSTALL file, i.e.:

# status.example.com maps to /var/www/status/
cd /var/www/status/
wget http://status.net/statusnet-0.9.6.tar.gz
tar -xzf statusnet-0.9.6.tar.gz --strip-components=1
rm statusnet-0.9.6.tar.gz
cd ..
chgrp www-data status/
chmod g+w status/
cd status/
chmod a+w avatar/ background/ file/

mysqladmin -u "root" -p "sql-root-password" create statusnet
mysql -u root -p
GRANT ALL on statusnet.* TO 'statusnetuser'@'localhost' IDENTIFIED BY 'statusnet-secret-password';

To Change default behaviour of URls to be more SEO friendly and not to show .php in URL (e.g. add so called fancy URLs – described in INSTALL):

cp htaccess.sample .htaccess


Then had to configure a VirtualHost under a subdomain http://statusnet.yourdomain.com/install.php or you can alternatively install and access it in browser via http://your-domain.com/status/install.php

An important note to open here is you have to set the URLs via which status.net will be accessed further before proceeding with the install, if you will be using HTTPS here is time to configure it and test it before proceeding with install …  Just be warned that if you don't set the URLs properly now and try to modify them further you will get a lot of issues hard to solve which will cost you a lot of time and nervee ..

If you want to enable twitter bridging in Statusnet you will need to get Twitter consumer and secret keys, to get that you have to create new application on https://dev.twitter.com/apps afterwards you will be taken to a page containing Consumer Key & Consumer Secret string.
StatusNet installation will auto generate config.php, you can further edit it manually with text editor. Content of my current statusnet config.php is here.

Most important options to change are:

$config['daemon']['user'] = 'www-data';
$config['daemon']['group'] = 'www-data';

www-data is user with which Apache is running by default on Debian Linux.

$config['site']['profile'] = 'private';

By default Status.Net will be set to run as private – e.g. it will be fitted for priv. use – messages posted will not publicly be visible. Here the possible options to choose between are:

$config['site']['profile'] = 'private';
$config['site']['profile'] = 'community';
$config['site']['profile'] = 'singleuser';
$config['site']['profile'] = 'public';

singleuser is pretty self explanatory, setting public option will open registration for any user on the internet – probably your network will quickly be filled with spam – so beware with this option. community will make statusnet publicly visible but, registration will only possible via use creation / invitation to join the network from admin.

vi /var/www/status/config.php
$config['site']['fancy'] = true;

Then to enable twitter to statusnet bridge add to config.php

vi /var/www/status/config.php

addPlugin('TwitterBridge');
$config['twitter']['enabled'] = true;
$config['twitterimport']['enabled'] = true;
$config['avatar']['path'] = '/avatar';
$config['twitter']['consumer_key'] = 'XXXXXXXX';
$config['twitter']['consumer_secret'] = 'XXXXXXXX';
# disable sharing location by default
$config['location']['sharedefault'] = 'false';

Notice, I decided to disable statusnet sharedefault folder, because i don't have a lot of free space to provide to users. If you want to let users be allowed to share files (you the space for that), you might want to set a maximum quote of uploaded files (to prevent your webserver from being DoSed – for example by too many huge uploads), here is some reasonable settings:
 

$config['attachments']['file_quota'] = 7000000;
$config['attachments']['thumb_width'] = 400;
$config['attachments']['thumb_height'] = 300;

 

If you want to get the best out of performance of your new statusnet microblogging service, after each modification of config.php be sure to run:

 

php scripts/checkschema.php

Running checkschema.php is also useful, to check whether adding new plugins to check whether plugin will not throw an error.

Here is some extra useful config.php plugins to enable:
 

addPlugin('Gravatar', array());
#addPlugin('Textile');
addPlugin('InfiniteScroll');
addPlugin('Realtime');
addPlugin('Blog');
addPlugin('SiteNoticeInSidebar');
addPlugin('WikiHashtags');
addPlugin('SubMirror');
addPlugin('LinkPreview');
addPlugin('Blacklist');


If you expect to have quickly growing base of users it is recommended to also check out whether your MySQL is tuned with mysqltuner and optimize it for performance

Another useful think you would like to do is to increased the number of Statusnet avatars in the 'following' – 'followers' – 'groups' sections on my profile page by editing

lib/groupminilist.php

and

lib/profileminilist.php

line 36 in both files.
To get the full list of possible variables that can be set in config.php run in terminal:

 php scripts/setconfig.php -a

If you happen to encounter some oddities and issues with StatusNet after installation, this is most likely to some PHP hardering on compile time or some PHP.ini functions disabled for security or some missing component to install which is described as a prerequirement in statusnet INSTALL file

to debug the issues enable statusnet logging by adding in config.php

$config['site']['logdebug'] = true;
$config['site']['logfile'] = '/var/log/statusnet.log';

By default logs produced will be quite verbose and there will be plenty of information you will probably not need and will lead to a lot of "noise", to get around this, there is the LogFilter Plugin for some reasonable logging use in config.php:

addPlugin('LogFilter', array( 'priority' => array(LOG_ERR => true,
LOG_INFO => true,
LOG_DEBUG => false),
'regex' => array('/About to push/i' => false,
'/twitter/i' => false,
'/Successfully handled item/i' => false)
));

If you want tokeep log of statusnet it is a good idea to rorate logs periodically to keep them from growing too big, to do this create in /etc/logrotate.d new files /etc/logrotate.d/statusnet with following content:

/var/log/statusnet/*.log {
daily
missingok
rotate 7
compress
delaycompress
notifempty
create 770 www-data www-data
sharedscripts
postrotate
/path/to/statusnet/scripts/stopdaemons.sh > /dev/null
/path/to/statusnet/scripts/startdaemons.sh > /dev/null
endscript
}

You will probably want to to add new Links, next to StatusNet main navigation links for logged in users, this is possible by adding new line to

lib/primarynav.php

and

lib/secondarynav.php

You will have to add a PHP context like:

 $this->action->menuItem('https://pc-freak.net/blog/',
                              _m('MENU','Pc-Freak.Net Blog'),
                              _('A pC Freak Blog'),
                              false,
                              'nav_pcfreak');

Once you're done with installation, make sure you change permissions or move install.php from /var/www/status, otherwise someone might overwrite your config.php and mess your installation …

chmod 000 /var/www/status/install.php There is plenty of other things to do with StatusNet (Support for communication with Jabber XMPP protocol, notification via SMS etc. There are also some plugins to add more statusnet functionality.


Enjoy micro blogging ! 🙂

Apache increase loglevel – Increasing Apache logged data for better statistic analysis

Tuesday, July 1st, 2014

apache-increase-loglevel-howto-increasing-apache-logged-data-for-better-statistic-analysis
In case of development (QA) systems, where developers deploy new untested code, exposing Apache or related Apache modules to unexpected bugs often it is necessery to increase Apache loglevel to log everything, this is done with:

 

LogLevel debug

LogLevel warn is common logging option for Apache production webservers.
 

Loglevel warn


in httpd.conf is the default Apache setting for Log. For some servers that produce too many logs this setting could be changed to LogLevel crit which will make the web-server log only errors of critical importance to webserver. Using LogLevel debug setting is very useful whether you have to debug issues with unworking (failing) SSL certificates. It will give you whole dump with SSL handshake and reason for it failing.

You should be careful before deciding to increasing server log level, especially on production servers.
Increased logging level puts higher load on Apache webserver, as well as produces a lot of gigabytes of mostly useless logs that could lead quickly to filling all free disk space.

If you  would like to increase logged data in access.log / error.log, because you would like to perform versatile statistical analisys on daily hits, unique visits, top landing pages etc. with Webalizer, Analog or Awstats.

Change LogFormat and CustomLog variables from common to combined.

By default Apache is logging with following LogFormat and Customlog
 

LogFormat "%h %l %u %t "%r" %>s %b" common
CustomLog logs/access_log common


Which will be logging in access.log format:

 

127.0.0.1 – jericho [10/Oct/2000:13:55:36 -0700] "GET /apache_pb.gif HTTP/1.0" 200 2326


Change it to something like:

 

LogFormat "%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-agent}i"" combined CustomLog log/access_log combined


This would produce logs like:

127.0.0.1 – jericho [10/Oct/2000:13:55:36 -0700] “GET /apache_pb.gif HTTP/1.0” 200 2326 “http://www.example.com/start.html” “Mozilla/4.08 [en] (Win98; I ;Nav)"

 

Using Combined Log Format produces all logged information from CustomLog … common, and also logs the Referrer and User-Agent headers, which indicate where users were before visiting your Web site page and which browsers they used. You can read rore on custom Apache logging tailoring theme on Apache's website

Finding spam sending php scripts on multiple sites servers – Tracing and stopping spammer PHP scripts

Monday, April 14th, 2014

stop_php_mail-spam-find-spammer-and-stop-php-spammer-websites
Spam has become a severe issue for administrators, not only for mail server admins but also for webshosting adms. Even the most secure spam protected mail server can get affected by spam due to fact it is configured to relay mail from other servers acting as web hosting sites.

Webhosting companies almost always suffer seriously from spam issues and often their mail servers gets blocked (enter spam blacklists), because of their irresponsible clients uploading lets say old vulnerable Joomla, WordPress without Akismet or proper spam handling plugin,a CMS which is not frequently supported / updated or custom client insecure php code.

What I mean is Shared server A is often configured to sent mail via (mail) server B. And often some of the many websites / scripts hosted on server A gets hacked and a spam form is uploaded and tons of spam start being shipped via mail server B.

Of course on mail server level it is possible to configure delay between mail sent and adopt a couple of policies to reduce spam, but the spam protection issue can't be completely solved thus admin of such server is forced to periodically keep an eye on what mail is sent from hosting server to mail server.
 


If you happen to be one of those Linux (Unix) webhosting admins who find few thousand of spammer emails into mail server logs or your eMail server queue and you can't seem to find what is causing it, cause there are multiple websites shared hosting using mainly PHP + SQL and you can't identify what php script is spamming by reviewing  Apache log / PHP files. What you can do is get use of:

PHP mail.log directive

Precious tool in tracking spam issues is a PHP Mail.log parameter, mail log paramater is available since PHP version >= 5.3.0 and above.
PHP Mail.log parameter records all calls to the PHP mail() function including exact PHP headers, line numbers and path to script initiating mail sent.

Here is how it is used:
 

1. Create empty PHP Mail.log file

touch /var/log/phpmail.log

File has to be writtable to same user with which Apache is running in case of Apache with SuPHP running file has to be writtable by all users.

On Debian, Ubunut Linux:

chown www:data:www-data /var/log/phpmail.log

On CentOS, RHEL, SuSE phpmail.log has to be owned by httpd:

chown httpd:httpd /var/log/phpmail.log

On some other distros it might be chown nobody:nobody etc. depending on the user with which Apache server is running.

 

2. Add to php.ini configuration following lines

mail.add_x_header = On
mail.log = /var/log/phpmail.log

PHP directive instructs PHP to log complete outbund Mail header sent by mail() function, containing the UID of the web server or PHP process and the name of the script that sent the email;
 

(X-PHP-Originating-Script: 33:mailer.php)


i.e. it will make php start logging to phpmail.log stuff like:
 

 

mail() on [/var/www/pomoriemonasteryorg/components/com_xmap/2ktdz2.php:1]: To: info@globalremarketing.com.au — Headers: From: "Priority Mail" <status_93@pomoriemon
astery.org> X-Mailer: MailMagic2.0 Reply-To: "Priority Mail" <status_93@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternative;boundary="——
—-13972215105347E886BADB5"
mail() on [/var/www/pomoriemonasteryorg/components/com_xmap/2ktdz2.php:1]: To: demil7167@yahoo.com — Headers: From: "One Day Shipping" <status_44@pomoriemonastery.
org> X-Mailer: CSMTPConnectionv1.3 Reply-To: "One Day Shipping" <status_44@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternative;boundary="—
——-13972215105347E886BD344"
mail() on [/var/www/pomoriemonasteryorg/components/com_xmap/2ktdz2.php:1]: To: domainmanager@nadenranshepovser.biz — Headers: From: "Logistics Services" <customer.
id86@pomoriemonastery.com> X-Mailer: TheBat!(v3.99.27)UNREG Reply-To: "Logistics Services" <customer.id86@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: mult
ipart/alternative;boundary="———-13972215105347E886BF43E"
mail() on [/var/www/pomoriemonasteryorg/components/com_xmap/2ktdz2.php:1]: To: bluesapphire89@yahoo.com — Headers: From: "Priority Mail" <status_73@pomoriemonaster
y.org> X-Mailer: FastMailer/Webmail(versionSM/1.2.6) Reply-To: "Priority Mail" <status_73@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternativ
e;boundary="———-13972215105347E886C13F2"

 

On Debian / Ubuntu Linux to enable this logging, exec:

echo 'mail.add_x_header = On' >> /etc/php5/apache2/php.ini
echo 'mail.log = /var/log/phpmail.log' >> /etc/php5/apache2/php.ini


I find it useful to symlink /etc/php5/apache2/php.ini to /etc/php.ini its much easier to remember php location plus it is a standard location for many RPM based distros.

ln -sf /etc/php5/apache2/php.ini /etc/php.ini

Or another "Debian recommended way" to enable mail.add_x_header logging on Debian is via:

echo 'mail.add_x_header = On' >> /etc/php5/conf.d/mail.ini
echo 'mail.log = /var/log/phpmail.log' >> /etc/php5/conf.d/mail.ini

On Redhats (RHEL, CentOS, SuSE) Linux issue:

echo 'mail.add_x_header = On' >> /etc/php.ini
echo 'mail.log = /var/log/phpmail.log' >> /etc/php.ini

3. Restart Apache

On Debian / Ubuntu based linuces:

/etc/init.d/apache2 restart

P.S. Normally to restart Apache without interrupting client connections graceful option can be used, i.e. instead of restarting do:

/etc/init.d/apache2 graceful

On RPM baed CentOS, Fedora etc.:

/sbin/service httpd restart

or

apachectl graceful
 

4. Reading the log

To review in real time exact PHP scripts sending tons of spam tail it:

tail -f /var/log/phpmail.log

 

mail() on [/var/www/remote-admin/wp-includes/class-phpmailer.php:489]: To: theosfp813@hotmail.com — Headers: Date: Mon, 14 Apr 2014 03:27:23 +0000 Return-Path: wordpress@remotesystemadministration.com From: WordPress Message-ID: X-Priority: 3 X-Mailer: PHPMailer (phpmailer.sourceforge.net) [version 2.0.4] MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="UTF-8"
mail() on [/var/www/pomoriemonasteryorg/media/rsinstall_4de38d919da01/admin/js/tiny_mce/plugins/inlinepopups/skins/.3a1a1c.php:1]: To: 2070ccrabb@kiakom.net — Headers: From: "Manager Elijah Castillo" <elijah_castillo32@pomoriemonastery.com> X-Mailer: Mozilla/5.0 (Windows; U; Windows NT 5.0; es-ES; rv:1.9.1.7) Gecko/20100111 Thunderbird/3.0.1 Reply-To: "Manager Elijah Castillo" <elijah_castillo32@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternative;boundary="———-1397463670534B9A76017CC"
mail() on [/var/www/pomoriemonasteryorg/media/rsinstall_4de38d919da01/admin/js/tiny_mce/plugins/inlinepopups/skins/.3a1a1c.php:1]: To: 20wmwebinfo@schools.bedfordshire.gov.uk — Headers: From: "Manager Justin Murphy" <justin_murphy16@pomoriemonastery.com> X-Mailer: Opera Mail/10.62 (Win32) Reply-To: "Manager Justin Murphy" <justin_murphy16@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternative;boundary="———-1397463670534B9A7603ED6"
mail() on [/var/www/pomoriemonasteryorg/media/rsinstall_4de38d919da01/admin/js/tiny_mce/plugins/inlinepopups/skins/.3a1a1c.php:1]: To: tynyrilak@yahoo.com — Headers: From: "Manager Elijah Castillo" <elijah_castillo83@pomoriemonastery.com> X-Mailer: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; pl; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 Reply-To: "Manager Elijah Castillo" <elijah_castillo83@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternative;boundary="———-1397463670534B9A7606308"
mail() on [/var/www/pomoriemonasteryorg/media/rsinstall_4de38d919da01/admin/js/tiny_mce/plugins/inlinepopups/skins/.3a1a1c.php:1]: To: 2112macdo1@armymail.mod.uk — Headers: From: "Manager Justin Murphy" <justin_murphy41@pomoriemonastery.com> X-Mailer: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; pl; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 Reply-To: "Manager Justin Murphy" <justin_murphy41@pomoriemonastery.com> Mime-Version: 1.0 Content-Type: multipart/alternative;boundary="———-1397463670534B9A76086D1"

 

As you can see there is a junky spam mails sent via some spammer script uploaded under name .3a1a1c.php, so to stop the dirty bastard, deleted the script:

rm -f /var/www/pomoriemonasteryorg/media/rsinstall_4de38d919da01/admin/js/tiny_mce/plugins/inlinepopups/skins/.3a1a1c.php

It is generally useful to also check (search) for all hidden .php files inside directoring storing multiple virtualhost websites, as often a weirdly named hidden .php is sure indicator of either a PHP Shell script kiddie tool or a spammer form.

Here is how to Find all Hidden Perl / PHP scripts inside /var/www:

find . -iname '.*.php'
./blog/wp-content/plugins/fckeditor-for-wordpress-plugin/ckeditor/plugins/selection/.0b1910.php
./blog/wp-content/plugins/fckeditor-for-wordpress-plugin/filemanager/browser/default/.497a0c.php
./blog/wp-content/plugins/__MACOSX/feedburner_feedsmith_plugin_2.3/._FeedBurner_FeedSmith_Plugin.php

find . -iname '.*.pl*'

….

Reviewing complete list of all hidden files is also often useful to determine shitty cracker stuff

 find . -iname ".*"

Debugging via  /var/log/phpmail.log enablement is useful but is more recommended on development and staging (QA) environments. Having it enable on productive server with high amounts of mail sent via PHP scripts or just on dedicated shared site server could cause both performance issues, hard disk could quickly get and most importantly could be a severe security hole as information from PHP scripts could be potentially exposed to external parties.

Tracking multiple log files in real time in Linux console / terminal (MultiTail)

Monday, July 29th, 2013

Multitail multiple tail Debian GNU Linux viewing Apache access and error log in shared screen
Whether you have to administer Apache, Nginx or Lighttpd, or whatever other kind of daemon which interactively logs user requests or errors you probably already know well of tail command (tail -f /var/log/apache2/access.log) is something Webserver Linux admin can't live without. Sometimes however you have number of Virtualhost (domains) each configured to log site activity in separate log file. One solution to the problem is to use GNU Screen (screen – terminal emulator) to launch multiple screen session and launch separate tail -f /var/log/apache2/domain1/access.log , tail -f /var/log/apache2/domain2/access.log etc. This however is a bit of hack and except configuring screen to show multiple windows on one Virtual Terminal (tty or vty in gnome), you can't really see output simultaneously in one separated window.

Here is where multitail comes handy. MultiTail is tool to visualize in real time log records output of multiple logs (tails) in one shared terminal Window. MultiTail is written to use ncurses library used by a bunch of other useful tools like Midnight Command so output is colorful and very nice looking.

Here is MultiTail package description on Debian Linux:

linux:~# apt-cache show multitail|grep -i description -A 1
Description-en: view multiple logfiles windowed on console
 multitail lets you view one or multiple files like the original tail

Description-md5: 5e2f688efb214b063bdc418a705860a1
Tag: interface::text-mode, role::program, scope::utility, uitoolkit::ncurses,
root@noah:/home/hipo# apt-cache show multitail|grep -i description -A 1
Description-en: view multiple logfiles windowed on console
 multitail lets you view one or multiple files like the original tail

Description-md5: 5e2f688efb214b063bdc418a705860a1
Tag: interface::text-mode, role::program, scope::utility, uitoolkit::ncurses,
 

Multiple Tail is available across most Linux distributions to install on Debian / Ubuntu / Mint etc. Linux:

debian:~# apt-get install --yes multitail
...

On recent Fedora / RHEL / CentOS etc. RPM based Linuces to install:

[root@centos ~]# yum -y install multitail
...

On FreeBSD multitail is available to install from ports:

freebsd# cd /usr/ports/sysutils/multitail
freebsd# make install clean
...

Once installed to display records in multiple files lets say Apache domain name access.log and error.log

debian:~# multitail -f /var/log/apache2/access.log /var/log/apache2/error.log

It has very extensive help invoked by simply pressing h while running

multtail-viewing-in-gnome-shared-screen-debian-2-log-files-screenshot

Even better multitail is written to already have integrated color schemes for most popular Linux services log files

multitail multiple tail debian gnu linux logformat different color schemes screenshot
List of supported MulLog Color schemes as of time of writting article is:

acctail, acpitail, apache, apache_error, argus, asterisk, audit, bind, boinc, boinctail ,checkpoint, clamav, cscriptexample, dhcpd, errrpt, exim, httping, ii, inn, kerberos, lambamoo, liniptfw, log4j, mailscanner, motion, mpstat, mysql, nagtail, netscapeldap, netstat, nttpcache, ntpd, oracle, p0f, portsentry, postfix, pptpd, procmail, qmt-clamd, qmt-send, qmt-smtpd, qmt-sophie, qmt-spamassassin, rsstail, samba, sendmail, smartd, snort spamassassin, squid, ssh, strace, syslog, tcpdump, vmstat, vnetbr, websphere, wtmptail

To tell it what kind of log Color scheme to use from cmd line use:

debian:~# multitail -Csapache /var/log/apache2/access.log /var/log/apache2/error.log

multiple tail with Apache highlight on Debian Linux screenshot

Useful feature is to run command display in separate Windows while still following log output, i.e.:

[root@centos:~]# multitail /var/log/httpd.log -l "netstat -nat"
...

Multitail can also merge output from files in one Window, while in second window some other log or command output is displayed. To merge output from Apache access.log and error.log:

debian:~# multitail /var/log/apache2/access.log -I /var/log/apache2/error.log

When merging two log files output to show in one Window it is useful to display each file output in different color for the sake of readability

For example:
 

debian:~# multitail -ci green /var/log/apache/access.log -ci red -I /var/log/apache/error.log

multitail merged Apache access and error log on Debian Linux

To display output from 3 log files in 3 separate shared Windows in console use:

linux:~# multitail -s 2 /var/log/syslog /var/log/apache2/access.log /var/log/apache2/error.log

For some more useful examples, check out MultiTail's official page examples
There is plenty of other useful things to do with multitail, for more RTFM 🙂

Linux PHP Disable chmod() and chown() functions for better Apache server security

Monday, July 15th, 2013

php_tighten_security_by_enabling_safe_mode-php-ini-function-prevent-crackers-break-in-your-server
I have to administer few inherited Linux servers with Ubuntu and Debian Linux. The servers hosts mainly websites with regularly un-updated Joomlas and some custom developed websites which were developed pretty unsecure. To mitigate hacked websites I already disabled some of most insecure functions like system(); eval etc. – I followed literally my previous tutorial PHP Webhosting security disable exec();, system();, open(); and eval();
Still in logs I see shits like:
 

[error] [client 66.249.72.100] PHP Warning:  mkdir(): No such file or directory in /var/www/site/plugins/system/jfdatabase/intercept.jdatabasemysql.php on line 161

Hence to prevent PHP mkdir(); and chown(); functiosn being active, I had to turn on in /etc/php5/apache2/php.ini – safe_mode . For some reason whoever configured Apache leave it off.

safe_mode = on

Hopefully by disabling this functions will keep cracker bot scripts to not create some weird directory structures on HDD or use it as mean to DoS overflow servers filesystem.

Hope this help others stabilize their servers too. Enjoy ! 🙂

Fixing Clamav error: “WARNING: Can’t download daily.cvd from database.clamav.net”

Thursday, June 6th, 2013

On one of the Debian Squeeze Servers, where I have Running QMAIL Server, I haven't checked logs for a long time. Cause Qmail is configured and all runs smoothly. Just today while checking logs, I've noticed in /var/log/clamav/clamav.log, clamav database fails to be updated with an error, e.g.:

qmail:~# tail -n 28 /var/log/clamav/clamav.log

ClamAV update process started at Thu Jun 6 20:47:14 2013
main.cvd is up to date (version: 54, sigs: 1044387, f-level: 60, builder: sven)
WARNING: getpatch: Can't download daily-16682.cdiff from db.local.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from db.local.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from db.local.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from db.local.clamav.net
ERROR: getpatch: Can't download daily-16682.cdiff from db.local.clamav.net
WARNING: Incremental update failed, trying to download daily.cvd
ERROR: Can't download daily.cvd from db.local.clamav.net
Giving up on db.local.clamav.net…
ClamAV update process started at Thu Jun 6 20:47:15 2013
main.cvd is up to date (version: 54, sigs: 1044387, f-level: 60, builder: sven)
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: Incremental update failed, trying to download daily.cvd
WARNING: Can't download daily.cvd from database.clamav.net
Trying again in 5 secs…
ClamAV update process started at Thu Jun 6 20:47:20 2013
main.cvd is up to date (version: 54, sigs: 1044387, f-level: 60, builder: sven)
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net
WARNING: Incremental update failed, trying to download daily.cvd
WARNING: Can't download daily.cvd from database.clamav.net

On host Freshclam is configured to run in background as a service i.e.:

qmail:~#
 ps ax|grep -i fresh|grep -v grep
13615 ? Ss 0:02 /usr/bin/freshclam -d –quiet
 

I stopped clamav and tried running it manually through its script: qmail:~# /etc/init.d/clamav-freshclam restart

The error was reoccuring, so I decided to kill it and try running freshclam manually:

qmail:~# kill -9 freshclam

qmail:~# freshclam
I got same error again:
 

Thu Jun 6 16:46:20 2013 -> ClamAV update process started at Thu Jun 6 16:46:20 2013 Thu Jun 6 16:46:20 2013 -> main.cvd is up to date (version: 54, sigs: 1044387, f-level: 60, builder: sven) Thu Jun 6 16:46:20 2013 -> WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net Thu Jun 6 16:46:20 2013 -> WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net Thu Jun 6 16:46:20 2013 -> WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net Thu Jun 6 16:46:20 2013 -> WARNING: getpatch: Can't download daily-16682.cdiff from database.clamav.net Thu Jun 6 16:46:20 2013 -> ERROR: getpatch: Can't download daily-16682.cdiff from database.clamav.net Thu Jun 6 16:46:20 2013 -> WARNING: Incremental update failed, trying to download daily.cvd Thu Jun 6 16:46:20 2013 -> ERROR: Can't download daily.cvd from database.clamav.net Thu Jun 6 16:46:20 2013 -> Giving up on database.clamav.net… Thu Jun 6 16:46:20 2013 -> Update failed. Your network may be down or none of the mirrors listed in /etc/clamav/freshclam.conf is working. Check http://www.clamav.net/support/mirror-problem for possible reasons.

The solution was to delete clamav database filedaily.cvd and then run another freshclam Clamav DB virus update:

qmail:~# rm -f /var/lib/clamav/daily.cvd
qmail:~# freshclam
root@pcfreak:/etc/init.d# freshclam ClamAV update process started at Thu Jun 6 22:07:21 2013
main.cvd is up to date (version: 54, sigs: 1044387, f-level: 60, builder: sven)
Downloading daily.cvd [100%]
daily.cvd updated (version: 17309, sigs: 1302714, f-level: 63, builder: neo)
bytecode.cld is up to date (version: 214, sigs: 41, f-level: 63, builder: neo)
Database updated (2347142 signatures) from db.local.clamav.net (IP: 195.222.33.229)

Finally, to make freshclam work as daemon, restarted init script:

qmail:~# /etc/init.d/clamav-freshclam restart
[ ok ] Stopping ClamAV virus database updater: freshclam.
[ ok ] Starting ClamAV virus database updater: freshclam.