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Ubuntu 12.10 – Switch to MATE

Dhaval Thakar — Mon, 22 Apr 2013 12:57:21 +0000

Ubuntu 12.10 – Switch to MATE.
This post will help you to switch from Unity to Mate Desktop on Ubuntu 12.10

Install MATE

#ADD Anyone
sudo add-apt-repository "deb http://packages.mate-desktop.org/repo/ubuntu quantal main"
sudo add-apt-repository "deb http://repo.mate-desktop.org/ubuntu quantal main"
sudo add-apt-repository "deb http://mirror1.mate-desktop.org/ubuntu quantal main"
 
sudo apt-get update
sudo apt-get install mate-archive-keyring
sudo apt-get update
sudo apt-get install mate-core
sudo apt-get install mate-desktop-environment

Now you can logoff & login using MATE desktop enviroment, if you wish to completely remove Unity, following commands will help.

Remove Unity

sudo apt-get --yes purge unity 
sudo apt-get --yes purge unity-asset-pool unity-services 
sudo apt-get --yes purge unity-lens-* unity-scope-* ubuntu-webapps-*
sudo apt-get --yes purge unity-common
sudo apt-get --yes purge libunity-misc4 libunity-core-6* libunity-webapps*
sudo apt-get --yes purge gir1.2-unity-*
sudo apt-get --yes purge liboverlay-scrollbar* overlay-scrollbar*
sudo apt-get --yes purge appmenu-gtk appmenu-gtk3 appmenu-qt
sudo apt-get --yes purge libufe-xidgetter0
sudo apt-get --yes purge xul-ext-unity xul-ext-websites-integration
sudo apt-get --yes purge firefox-globalmenu thunderbird-globalmenu

Install Citrix XenServer using PXE

Dhaval Thakar — Mon, 28 Jan 2013 19:41:31 +0000

This post covers how to Install Citrix XenServer using pxe.
As a prerequisite you need to have tftp server configured.

Create tftp dir for xenserver

mkdir -p /tftpboot/images/xenserver

Mount & copy required boot files from xenserver iso

mount -o loop  /downloads/XenServer-6.1-install-cd.iso /tmp/cd/
cd /tftpboot/images/xenserver
cp `find /tmp/cd/ -name install.img` ./
cp `find /tmp/cd/ -name vmlinuz` ./
cp `find /tmp/cd/ -name xen.gz` ./

Append following lines in /tftpboot/pxelinux.cfg/default

label Install Citrix XenServer 
kernel mboot.c32
append images/xenserver/xen.gz dom0_max_vcpus=1-2 dom0_mem=752M,max:752M com1=115200,8n1 console=com1,vga --- images/xenserver/vmlinuz xencons=hvc console=hvc0 console=tty0 --- images/xenserver/install.img

Now you can install xenserver using pxe. You can use http / local / nfs as image source.
We have tested installation using http only. You can mount xen iso on html chile path & use it for installation.
e.g http://192.168.1.1/yum/xen/

If you wish to skip installation methods (http/local/nfs) & start installation using pxe, you can use answer file.
Append following lines in /tftpboot/pxelinux.cfg/default

label Install Citrix XenServer 
kernel mboot.c32
append images/xenserver/xen.gz dom0_max_vcpus=1-2 dom0_mem=752M,max:752M com1=115200,8n1 console=com1,vga --- images/xenserver/vmlinuz xencons=hvc console=hvc0 console=tty0 answerfile_device=eth0 answerfile=http://192.168.1.1/yum/xenfile --- images/xenserver/install.img

Sample answer file, here we have defined path http://192.168.1.1/yum/xenfile

<?xml version="1.0"?>
<installation srtype="ext">
<primary-disk>sdaprimary-disk>
<keymap>uskeymap>
<root-password>mypasswordroot-password>
<source type="url">http://192.168.1.1/yum/xen/source>
<admin-interface name="eth0" proto="dhcp" />
<timezone>Asia/Indiatimezone>
installation>

Be cautious using above answer file, this will erase /dev/sda & install fresh xenserver.

How to Disable Graphical Boot & Shutdown on Fedora

Dhaval Thakar — Thu, 24 Jan 2013 12:32:37 +0000

If you are not a fan of graphical boot / shutdown & wish to disable it, this post will explain how to disable.

sudo vi /etc/sysconfig/grub 
#change from
GRUB_CMDLINE_LINUX="rd.md=0 rd.lvm=0 rd.dm=0 $([ -x /usr/sbin/rhcrashkernel-param ] && /usr/sbin/rhcrashkernel-param || :) rd.luks=0 vconsole.keymap=us rhgb quiet"
#change to 
GRUB_CMDLINE_LINUX="rd.md=0 rd.lvm=0 rd.dm=0 $([ -x /usr/sbin/rhcrashkernel-param ] && /usr/sbin/rhcrashkernel-param || :) rd.luks=0 vconsole.keymap=us  quiet"
#here we have removed rhgb
sudo grub2-mkconfig -o /boot/grub2/grub.cfg

You can certainly remove rhgb from /boot/grub2/grub.cfg to get same result, but after kernel upgrade you’ll again get graphical boot & shutdown. Whereas making changes in /etc/sysconfig/grub permanent.

Fedora 18 switch to MATE Desktop

Dhaval Thakar — Thu, 17 Jan 2013 11:57:04 +0000

Fedora 18 is released with support for MATE desktop. For previous release one had to install MATE from third party repository. Whereas with latest version you can get MATE support with single command.

To install MATE

yum groupinstall MATE

Like me if you are not willing to use Gnome 3 at all, you can remove gnome & install mate with following commands. First of all switch to init 3 or shell using ctrl+shift+function_key

yum groupremove GNOME
yum groupinstall MATE

Upgrade Fedora 17 to 18 using fedup OR fedora-upgrade

Dhaval Thakar — Wed, 16 Jan 2013 11:33:09 +0000

Apart from using yum upgrade, you can also use fedup OR fedora-upgrade to upgrade fedora to latest version available.

Using fedup
With fedora 18 fedup replaces preuprade utility. It basically downloads boot images & required packages to upgrade from all repositories like rpmforge, dropbox etc. Once packages are downloaded you’ll be asked to reboot machine.

sudo yum --enablerepo=updates-testing install fedup
#32bit
sudo fedup-cli --network 18 --instrepo http://dl.fedoraproject.org/pub/fedora/linux/releases/18/Fedora/i386/os/
 
#64bit
sudo fedup-cli --network 18 --instrepo http://dl.fedoraproject.org/pub/fedora/linux/releases/18/Fedora/x86_64/os/

Once packages are successfully downloaded you’ll get prompt to reboot.
setting up system for upgrade
Finished. Reboot to start upgrade.

One reboot system will boot to System upgrade (fedup)
Once finished you’ll get Fedora 18 screen.

Using fedora-upgrade.
fedora-upgrade uses yum to install required packages.

sudo yum install fedora-upgrade 
sudo fedora-upgrade

Upgrade Fedora 17 to 18 -using shell

Dhaval Thakar — Tue, 15 Jan 2013 17:17:34 +0000

This post explains howto Upgrade Fedora 17 to 18 using shell.

32bit

rpm --import https://fedoraproject.org/static/DE7F38BD.txt
rpm -Uvh http://download.fedoraproject.org/pub/fedora/linux/releases/18/Everything/i386/os/Packages/f/fedora-release-18-1.noarch.rpm
yum upgrade yum* -y
yum upgrade -y

64bit

rpm --import https://fedoraproject.org/static/DE7F38BD.txt
rpm -Uvh http://download.fedoraproject.org/pub/fedora/linux/releases/18/Everything/x86_64/os/Packages/f/fedora-release-18-1.noarch.rpm
yum upgrade yum* -y
yum upgrade -y

Here I had to remove qt-X11 to resolve yum upgrade error, qt-X11 was being used by Chrome.

Mirror SVN Repository

Dhaval Thakar — Mon, 14 Jan 2013 03:39:13 +0000

Mirror SVN Repository can be useful to offload server or If you have developers at different location OR you have requirement to keep offsite mirror ready for recovery.
I have used svn proxy. It works fine, but this can not be used for developers sitting in different location as this will not forward commit requests to master server.

Here
Master server 192.168.1.10
Slave server 192.168.222.10

Master httpd.conf

LoadModule dav_svn_module     /usr/lib/httpd/modules/mod_dav_svn.so
LoadModule authz_svn_module   /usr/lib/httpd/modules/mod_authz_svn.so
 
AuthType Basic
AuthName "SVN Authorization Realm"
AuthUserFile /etc/httpd/svn.passwd
Require valid-user
AuthzSVNAccessFile /etc/httpd/svn.authz
DAV svn
SVNParentPath /storage/svnroot/
SVNListParentPath On
SVNIndexXSLT "/repos-web/view/repos.xsl"
SVNPathAuthz off

Append followings in svn.authz

[/]
svnsync = r

Slave httpd.conf

LoadModule dav_svn_module   modules/mod_dav_svn.so
LoadModule authz_svn_module modules/mod_authz_svn.so
#below location is required to avoid loops when svnsync received from master repository
 
AuthType Basic
AuthName "SVN Authorization Realm"
AuthUserFile /etc/httpd/svn.passwd
Require valid-user
AuthzSVNAccessFile /etc/httpd/svn.authz
   DAV svn
   SVNParentPath /storage/svnroot/
   SVNListParentPath On
   Order deny,allow
   Deny from all
   Allow from 192.168.1.10 #master server
 
 
 
AuthType Basic
AuthName "SVN Authorization Realm"
AuthUserFile /etc/httpd/svn.passwd
Require valid-user
AuthzSVNAccessFile /etc/httpd/svn.authz
   DAV svn
   SVNParentPath /storage/svnroot/
SVNListParentPath On
SVNIndexXSLT "/repos-web/view/repos.xsl"
SVNPathAuthz off
#mention master repo url to forward commit requests.
SVNMasterURI http://192.168.1.10/svn/repos/

Slave Server Configuration,
Create blank repository

svnadmin create /storage/svnroot/project1
chown apache: /storage/svnroot/project1 -R

Append followings in svn.authz. svnsync needs rw access to update repo when svnsync received from server hook.

[/]
svnsync = rw

On Slave create pre-revprop-change for every repository
e.g project1/hooks/pre-revprop-change

cat pre-revprop-change
#!/bin/sh
USER="$3"
if [ "$USER" = "svnsync" ]; then exit 0; fi
echo "Only the svnsync user can change revprops" 2>&1
exit 1
 
chmod +x project1/hooks/pre-revprop-change

Configure svnsync

svnsync init --username svnsync --password mypassword file:///storage/svnroot/project1 http://192.168.1.10/svn/repos/project1
svnsync sync --username svnsync --password mypassword file:///storage/svnroot/project1

On Master create post-commit & post-revprop-change hooks under every repository. Here you can either use following script or replace MYREPO with repository names.
cat post-commit

#!/bin/bash
REPOS="$1"
MYREPO=`echo "$REPOS" |/bin/gawk -F"/" '{ print $4}'`
REV="$2"
USER="$3"
PROPNAME="$4"
ACTION="$5"
/bin/svnsync sync --non-interactive --username svnsync --password mypassword http://192.168.222.10/svnsync/"$MYREPO" &amp;
exit 0

cat post-revprop-change

#!/bin/bash
REPOS="$1"
MYREPO=`echo "$REPOS" |/bin/gawk -F"/" '{ print $4}'`
REV="$2"
USER="$3"
PROPNAME="$4"
ACTION="$5"
/bin/svnsync --non-interactive copy-revprops --username svnsync --password mypassword http://192.168.222.10/svnsync/"$MYREPO" "$REV" &amp;

With the above setup. Slave can be used as svn server for users located in remote office, their commit requests will be proxy to Master server. Once commit on master is complete, post-commit hook will start svnsync for Slave server.
Slave server can be useful to reduce load on master server by providing dedicated resource to check out code.

Fix Vnc Client blank screen on Mate Desktop – Fedora

Dhaval Thakar — Mon, 07 Jan 2013 02:22:07 +0000

By default when you run vncserver on Fedora box running gnome, you get desktop on vnc client connections.
Whereas with MATE as the only desktop environment, you’ll not get any display on vnc connection. All you get it blank screen. This is probably due to Mate-session is not mentioned in xstartup.

To get display on vnc client add following line in xstartup

/usr/bin/mate-session

E.g

head ~/.vnc/xstartup 
#!/bin/sh

vncconfig -iconic &
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
/usr/bin/mate-session

With newer vncserver session, you’ll not face blank vnc client screen.

Fedora – Mount partition without authentication

Dhaval Thakar — Tue, 01 Jan 2013 20:29:11 +0000

This article is for Fedora Gnome Shell users, who does not wish to enter root password while mounting partition as normal user.

You need to search & replace auth_admin_keep with yes from the following file.

/usr/share/polkit-1/actions/org.freedesktop.udisks2.policy

Or use following command

cp /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy.bak
sed -i 's/auth_admin_keep/yes/g' /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy

Once you are done with changes, you’ll not be prompted to enter root password for authentication.

OpenVpn drops connection after hour – fix.

Dhaval Thakar — Thu, 13 Dec 2012 07:56:26 +0000

Recently we noticed openvpn clients were disconnecting after every hour. We never realized it earlier as there was hardly any requirement to keep connection active for hours.

This is probably issue when openvpn is configured to auth users using pop3 or local system account, where user needs to enter user / pass.
Openvpn configured with default client cert may not face this.

Fix was easy but took me few hours to find it & configure appropriate settings.
All you need to do is enter following line in server & client configuration.

reneg-sec 86400

If reneg-sec is not mentioned default value of 3600 seconds is used. After every hour client is asked to reenter user / pass. If server doesn’t receive response / input in 60 sec client will disconnect with following error in server logs.

TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
TLS Error: TLS handshake failed

Why we need to enter reneg-sec in client conf ?
Lower value mentioned in reneg-sec is given preference. If you update server.conf & ignore to append client.conf, still user will disconnect after every hour.