| It's sometimes necessary during upgrades to disable pe-puppetdb ha-sync to prevent an unupgraded pdb from pulling data from a pdb that's already received the upgrade. Not disabling sync while upgrading could cause the sync process to enqueue duplicate commands if we change how a hash that's used in the sync summary query is calculated. We should create an admin endpoint that disables sync to guard against the case mentioned above. The command to disable sync should be able to persist across restarts. This could be accomplished by writing a file of the most recent disable-sync command the endpoint receives and then using that file to determine whether sync should be enabled during a restart, defaulting to sync enabled if the file isn't present. We should also add a way to query the status of sync to see if it is disabled. This will allow a client to check that the command to disable sync has been received and processed. Also worth looking into a way to allow clients to tell if a sync is in flight as that could be an another issue with upgrades. |
