resource-agents
resource-agents copied to clipboard
ClusterLabs
Enhance galera to interact over multiple clusters
This change adds a new resource agent "stretch_galera" which builds off of the existing "galera" agent. To accommodate this, the "galera" agent's shell script structure is modified slightly so that it can be sourced for its functions.
The new resource agent adds a new parameter "remote_node_map" to the Galera resource agent which allows it to consider galera node names that are in other clusters as part of its Galera quorum. To achieve this, it launches read-only pcs commands to the remote clusters in order to view and modify remote state variables.
Additionally, the stretch agent honors an optional pcs
attribute
TBH, this scares the heck out of me.
At the minimum, can we put this in a new agent (source the original then add the new functionality)?
I can see the need for special handling (what to do if the remote isn't reachable for example) that I'd not want to complicate the non-stretch version with.
@beekhof as far as sourcing the original, I will need to add a line to the case statement at the end that upon passing a command like "sourceonly" does a simple "return", to avoid the "exit" call. am not finding any bash magic to source all the variables and having them survive past an "exit".
@beekhof note this change no longer writes any data over SSH, and only reports status, and to that end we can also replace the usage of SSH with an xinetd service linked to a script. however, in the xinetd case, authentication and encryption go out the window as far as I understand being able to create xinetd services. the security audit will then say, if the xinetd script itself has a vulnerability, it's openly exposed.
another option is to use SSH but to limit the commands / scripts that the user can execute. this can be done either with a custom shell in /etc/passwd or apparently you can limit commands for a specific key in authorized_keys, been googling that a bit. I think having a "front end" that is reached via ssh but nonetheless is just a single script with an argument is the least we can do.
