SCI-CD

h1. Basic cluster management

h3. Check if all is ok

<pre>
gnt-cluster verify
</pre>

h3. Show detailed information

<pre>
gnt-(cluster|node|instance) info
</pre>

h3. List objects

Nodes
<pre>
gnt-node list
</pre>

Configured instances
<pre>
gnt-instance list
</pre>

h3. Create new instance

New instance on the NODE1 with failover on the NODE2, with one disk size 10Gb and 256M RAM.
INSTANCE_NAME must be resolvable via DNS.
<pre>
gnt-instance add -t drbd -o debootstrap+default -s 10g -B memory=256m -n NODE1:NODE2 INSTANCE_NAME
</pre>

Real example: create new instance
* on the node gnt2
* with failover on gnt1
* with three disks:
** 10g on volume group xenvg
** 600m on volume group xenvg (probably for swap)
* 5g on volume group xenvg
* DNS name vg-test1
* IP address will be configured automatically by resolving vg-test1' IP and matching it against @/etc/ganeti/networks@

<pre>
gnt-instance add -t drbd -o debootstrap+default --disk 0:size=10g,vg=xenvg --disk 1:size=600m,vg=xenvg --disk 2:size=5g,vg=newvg -B memory=256m -n gnt2:gnt1 vg-test1
</pre>

*NOTE:* the @vg=....@ option to specify different volume groups will be available since Ganeti 2.4.0 release.

h3. Instance import

For example, you have an image, tar, etc. of OS from other XEN(or physical) machine.
To start it on sci-cd you must add instance with --no-install flag:
<pre>
gnt-instance add -t drbd -B memory=5192m -n node1:node2 -o debootstrap+default --no-install --no-name-check --no-ip-check --net=0:link=dmz --disk 0:size=4G --disk 1:size=1024M --disk 2:size=100G --disk 3:size=50G terminal
</pre>
--no-namecheck used when machine name doesn't resolv in any ip(ip may resolve my dns or /etc/hosts)
--no-ip-check used when no ip provided while creating instance

h3. Instance manipulations

Various simple instance manipulations
<pre>
gnt-instance (startup|shutdown|reboot|failover|remove|console) INSTANCE
</pre>

h3. OS command execution

Run OS command on all nodes
<pre>
gnt-cluster command .....
</pre>

h2. SSH

All new instances, including 'sci' are going with empty root password and no ssh server installed.
You should first log in to the instance using @gnt-instance console INSTANCE@ command, then set
root's password using @passwd@ command and install ssh server using
<pre>
apt-get install openssh-server
</pre>