this is obsolete doc -- see http://doc.nethence.com/ instead

Setting up HA services with redhat/centos Cluster Suite (RHCS) 

on CentOS 6.7 

http://pbraun.nethence.com/unix/sysutils_linux/redhat-rhcs.html 

http://pbraun.nethence.com/unix/sysutils_linux/redhat-rhcs-services.html 

http://pbraun.nethence.com/unix/mail/davmail.html 

http://pbraun.nethence.com/unix/sysutils_linux/systemd.html 

Setting up failover domains 

For an unrestricted failover domain, on e.g. cnode1, 

ccs -h localhost --addfailoverdomain allnodes

ccs -h localhost --addfailoverdomainnode allnodes cnode1

ccs -h localhost --addfailoverdomainnode allnodes cnode2

ccs -h localhost --addfailoverdomainnode allnodes cnode3

check, 

ccs -h localhost --lsfailoverdomain

populate the changes, 

cman_tool version -r

Setting up services 

Define the resources you need for a service. For my davmail service, I need: 

- the binary and configuration files located in /usr/local/davmail/ (copied on all nodes), which is a symlink to ./davmail-version/ 

cd /usr/local/

scp -r davmail-linux-x86_64-4.7.1-2416 cnode2:/usr/local/

scp -r davmail-linux-x86_64-4.7.1-2416 cnode3:/usr/local/

cd /etc/init.d/

scp davmail cnode2:/etc/init.d/

scp davmail cnode3:/etc/init.d/

also make sure openjdk is installed 

also make sure postfix is disabled on port 25 

see [how to setup davmail](http://pbraun.nethence.com/unix/mail/davmail.html) 

on cnode2 and cnode3 also, 

cd /usr/local/

ln -s davmail-linux-x86_64-4.7.1-2416 davmail

cd ~/

ls -l /etc/init.d/davmail # already executable by scp

chkconfig --add davmail

chkconfig davmail off

- an LSB compilant [init script](http://pbraun.nethence.com/unix/sysutils_linux/systemd.html) to use the RHCS <script> statement. 

- a floating IP --> this will be a RHCS resource 

Disable the service at local system startup in case it is enabled, 

chkconfig --list | grep davmail

chkconfig davmail off

See available resource types, 

ccs -h localhost --lsresourceopts

ccs -h localhost --lsresourceopts ip

ccs -h localhost --lsresourceopts script

See available service options, 

ccs -h localhost --lsserviceopts

Add this into the <rm> statement, 

vi /etc/cluster/cluster.conf

<resources> 

<ip address="10.0.0.X" monitor_link="yes" sleeptime="5"/> 

<script file="/etc/init.d/davmail" name="davmail_service"/> 

</resources> 

<service autostart="0" domain="allnodes" name="davmail" recovery="relocate"> 

<ip ref="10.0.0.X"/> 

<script ref="davmail_service"/> 

</service> 

increment the configuration version, 

<cluster config_version="34" name="centosha">

check and populate the changes, 

ccs_config_validate

cman_tool version -r

Theorically you should also be able to setup this as follows (but we did it by hand), 

ccs -h localhost --addresource ip address=10.0.0.X minitor_links=yes sleeptime=5

ccs -h localhost --addservice davmail domain=allnodes recovery=relocate autostart=0

ccs -h localhost --addsubservice davmail ip ref=10.0.0.X

check, 

cat /etc/cluster/cluster.conf

Ready to go 

Check the the cluster is up and running, 

cman_tool nodes

clustat

Enable the service, 

clusvcadm -e davmail

#clusvcadm -e davmail -m cnode1

Check that the ip address is owned by the node on which the service has started, 

ip addr  

Refs. 

Why is the virtual IP address, managed by RHCS, not listed when using ifconfig?: https://access.redhat.com/solutions/127223 

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Cluster_Administration/s1-add-service-conga-CA.html 

Eventually check that the service is running using the local system, e.g., 

service davmail status

also test the service while you watch the logs, 

cd /usr/local/davmail/

tail -f davmaill.log

Once everything is fine enable autostart, 

vi /etc/cluster/cluster.conf

<cluster config_version="35" name="centosha">

<service autostart="1" domain="allnodes" name="davmail" recovery="relocate">

check and populate the changes, 

ccs_config_validate

cman_tool version -r

#ccs -h localhost --sync --activate

More commands 

Disable a service, 

clusvcadm -d davmail

Other services 

Share a common NFS mount point on all the nodes e.g., 

cat >> /etc/fstab <<EOF

nfs_server:/export/rhcs /mnt/ict-rhcs nfs4 _netdev,rw 0 0

EOF

mkdir -p /mnt/rhcs/

mount /mnt/rhcs/