Archive for January, 2016

How to mount NFS network filesystem to remote server via /etc/fstab on Linux

Friday, January 29th, 2016

If you have a server topology part of a project where 3 (A, B, C) servers need to be used to deliver a service (one with application server such as Jboss / Tomcat / Apache, second just as a Storage Server holding a dozens of LVM-ed SSD hard drives and an Oracle database backend to provide data about the project) and you need to access server A (application server) to server B (the Storage "monster") one common solution is to use NFS (Network FileSystem) Mount. 
NFS mount is considered already a bit of obsoleted technology as it is generally considered unsecre, however if SSHFS mount is not required due to initial design decision or because both servers A and B are staying in a serious firewalled (DMZ) dedicated networ then NTS should be a good choice.
Of course to use NFS mount should always be a carefully selected Environment Architect decision so remote NFS mount, imply  that both servers are connected via a high-speed gigabyte network, e.g. network performance is calculated to be enough for application A <-> to network storage B two sides communication not to cause delays for systems end Users.

To test whether the NFS server B mount is possible on the application server A, type something like:


mount -t nfs -o soft,timeo=900,retrans=3,vers=3, proto=tcp remotenfsserver-host:/home/nfs-mount-data /mnt/nfs-mount-point

If the mount is fine to make the mount permanent on application server host A (in case of server reboot), add to /etc/fstab end of file, following: /application/remote-application-dir-to-mount nfs   rw,bg,nolock,vers=3,tcp,timeo=600,rsize=32768,wsize=32768,hard,intr 1 2

If the NTFS server has a hostname you can also type hostname instead of above example sample IP, this is however not recommended as this might cause in case of DNS or Domain problems.
If you want to mount with hostname (in case if storage server IP is being commonly changed due to auto-selection from a DHCP server):

server-hostA:/application/local-application-dir-to-mount /application/remote-application-dir-to-mount nfs   rw,bg,nolock,vers=3,tcp,timeo=600,rsize=32768,wsize=32768,hard,intr 1 2

In above example you need to have the /application/local-application-dir-to-mount (dir where remote NFS folder will be mounted on server A) as well as the /application/remote-application-dir-to-mount
Also on server Storage B server, you have to have running NFS server with firewall accessibility from server A working.

The timeou=600 (is defined in) order to make the timeout for remote NFS accessibility 1 hour in order to escape mount failures if there is some minutes network failure between server A and server B, the rsize and wsize
should be fine tuned according to the files that are being red from remote NFS server and the network speed between the two in the example are due to environment architecture (e.g. to reflect the type of files that are being transferred by the 2)
and the remote NFS server running version and the Linux kernel versions, these settings are for Linux kernel branch 2.6.18.x which as of time of writting this article is obsolete, so if you want to use the settings check for your kernel version and
NTFS and google and experiment.

Anyways, if you're not sure about wsize and and rise, its perfectly safe to omit these 2 values if you're not familiar to it.

To finally check the NFS mount is fine,  grep it:


# mount|grep -i nfs
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
server-hostA:/application/remote-application-dir-to-mount on /application/remote-application-dir-to-mount type nfs (rw,bg,nolock,nfsvers=3,tcp,timeo=600,rsize=32768,wsize=32768,hard,intr,addr=

That's all enjoy 🙂



How to use wget and curl via HTTP Proxy server / How to set a HTTPS proxy server on a bash shell on Linux

Wednesday, January 27th, 2016


I've been working a bit on a client's automation, the task is to automate process of installations of Apaches / Tomcats / JBoss and Java servers, so me and colleagues don't waste too
much time in trivial things. To complete that I've created a small repository on a Apache with a WebDav server with major versions of each general branch of Application servers and Javas.
In order to access the remote URL where the .tar.gz binaries archives reside, I had to use a proxy serve as the client runs all his network in a DMZ and all Web Port 80 and 443 HTTPS traffic inside the client network
has to pass by the network proxy.

Thus to make the downloads possible via the shell script, writting I needed to set the script to use the HTTPS proxy server. I've been using proxy earlier and I was pretty aware of the http_proxy bash shell
variable thus I tried to use this one for the Secured HTTPS proxy, however the connection was failing and thanks to colleague Anatoliy I realized the whole problem is I'm trying to use http_proxy shell variable
which has to only be used for unencrypted Proxy servers and in this case the proxy server is over SSL encrypted HTTPS protocol so instead the right variable to use is:


The https_proxy var syntax, goes like this:

export https_proxy="$proxy_url"


Once the https_proxy variable is set  UNIX's wget non interactive download tool starts using the proxy_url variable set proxy and the downloads in my script works.

Hence to make the different version application archives download work out, I've used wget like so:

 wget –no-check-certificate –timeout=5

For other BSD / HP-UX / SunOS UNIX Servers where  shells are different from Bourne Again (Bash) Shell, the http_proxy and  https_proxy variable might not be working.
In such cases if you have curl (command line tool) is available instead of wget to script downloads you can use something like:

 curl -O -1 -k –proxy

The http_proxy and https_proxy variables works perfect also on Mac OS X, default bash shell, so Mac users enjoy.
For some bash users in some kind of firewall hardened environments like in my case, its handy to permanently set a proxy to all shell activities via auto login Linux / *unix scripts .bashrc or .bash_profile that saves the inconvenience to always
set the proxy so lynx and links, elinks text console browsers does work also anytime you login to shell.

Well that's it, my script enjoys proxying traffic 🙂

Windows “God Mode” one shortcut to see and configure all setttings in Microsoft Windows 7 / 8 / 10 – Windows Master Control Panel hidden feature

Monday, January 25th, 2016

One very handy "secret" feature of Windows Operating System which is very useful to people who administrate a dozen of Windows servers daily is called "God Mode".
The idea behind "God Mode" is pretty simple it aims to give you maximum control and viability concentrated in one single Window interface.

God Mode was quite a lot ranted over the past years so it is likely that many of my blog readers are already aware of that Windows secret, but for those who didn't it will be
nice to check it out. To see the God Mode Windows functionality just create a New Folder in Windows Desktop or Anywhere on the Windows PC and Rename the New Folder to:



By creating folder witth his text string you will be able to do almost everything you ever tend to do on Windows from changing the outlook of theme and mouse cursor, changing,
Win explorer's folder's options, modify fonts, change cursor blink rate, get windows performance tools and information, add / remove programs, modify language, modify
firewall settings and in short do everything that is provided by Control Panel + some other goodies like Administrative Tools, Restore Options, Event logs etc. grouped in a fantastic readable manner.
GodMode naming says it all more or less it aims to give you "Godlike" accessibility to the Windows. Of course to be able to properly use the feature you will have to create
the Folder named GodMode.{ED7BA470-8E54-465E-825C-99712043E01C} with Administrator user.
The GodMode is available in Windows OSes since quite a long (2007) and is documented officially by Microsoft

Another alternative shortcut that gives the Godmode Master control panel is:



Enjoy 🙂