Basic Instructuions for KNU Cluster Administrators and Operators

Root access to the nodes

Getting root access by means of su or sudo is prohibited.

Root's account password authentication works only from physical console and disabled via SSH.

Right way to get root access - key-based SSH connection.

List of admin's public SSH keys installed with dedicated RPM package. Manual keys addition to authorized_keys should be avoided.

Installing, Removing and Updating packages and configuration

All nodes configuration is Kickstart-based and packet-based only. All configuration packages had been installed from Blackjack-HKR repo.

Changing configs manually is stricly prohibited unless for negotiated testing and debug purposes.

Installing and removing packages manualy by means of yum install is stricly prohibited.

To add package additional Requires: dependencies should be added to knu-wn-deps package (commited to SVN). Then package need to be rebuilt and published.

To update packages immediately use yum nodesync command.

To update configuration files you should update corresponding package in SVN or create a new one in knu-config.spec.

If have no experience with RPM spec files or access to SVN - open new task in trac.

Managing services

KNU Cluster is RHEL7-based and use Systemd for services management. Get ready to works without LSB scripts and ​obtain systemd basic skills.

High Availablity services that should be maintened accross the cluster rely on Pacemaker operation.

Services under Pacemaker control SHOULD NOT be stoped/started/restarted manually! This includes:

• All clustered filesystems
• A-nodes DRBD
• A-nodes NFS
• A-nodes FhGFS Management LXC container
• PBS Mom
• FhGFS Client

In case of node/service maintenance that should be done without Pacemaker interaction, corresponding node SHOULD BE put into standby mode with pcs cluster standby <node>. To unstandby use pcs cluster unstandby <node>.