8.12. Scheduling of Snapshots
Snapshot scheduler creates snapshots automatically based on the configured scheduled interval of time. The snapshots can be created every hour, a particular day of the month, particular month, or a particular day of the week based on the configured time interval. The following sections describes scheduling of snapshots in detail.
8.12.1. Prerequisites
- To initialize snapshot scheduler on all the nodes of the cluster, execute the following command:
snap_scheduler.py init
This command initializes the snap_scheduler and interfaces it with the crond running on the local node. This is the first step, before executing any scheduling related commands from a node.Note
This command has to be run on all the nodes participating in the scheduling. Other options can be run independently from any node, where initialization has been successfully completed. - A shared storage named
gluster_shared_storageis used across nodes to co-ordinate the scheduling operations. This shared storage is mounted at /var/run/gluster/shared_storage on all the nodes. For more information see, Section 11.12, “Setting up Shared Storage Volume” - All nodes in the cluster have their times synced using NTP or any other mechanism. This is a hard requirement for this feature to work.
- If you are on Red Hat Enterprise Linux 7.1 or later, set the
cron_system_cronjob_use_sharesboolean toonby running the following command:# setsebool -P cron_system_cronjob_use_shares on
8.12.2. Snapshot Scheduler Options
Note
There is a latency of one minute, between providing a command by the helper script and for the command to take effect. Hence, currently, we do not support snapshot schedules with per minute granularity.
Enabling Snapshot Scheduler
To enable snap scheduler, execute the following command:
snap_scheduler.py enable
Note
Snapshot scheduler is disabled by default after initialization
For example:
# snap_scheduler.py enable snap_scheduler: Snapshot scheduling is enabled
Disabling Snapshot Scheduler
To enable snap scheduler, execute the following command:
snap_scheduler.py disable
For example:
# snap_scheduler.py disable snap_scheduler: Snapshot scheduling is disabled
Displaying the Status of Snapshot Scheduler
To display the the current status(Enabled/Disabled) of the snap scheduler, execute the following command:
snap_scheduler.py status
For example:
# snap_scheduler.py status snap_scheduler: Snapshot scheduling status: Disabled
Adding a Snapshot Schedule
To add a snapshot schedule, execute the following command:
snap_scheduler.py add "Job Name" "Schedule" "Volume Name"
where,
Job Name: This name uniquely identifies this particular schedule, and can be used to reference this schedule for future events like edit/delete. If a schedule already exists for the specified Job Name, the add command will fail.
Schedule: The schedules are accepted in the format crond understands. For example:
Example of job definition: .---------------- minute (0 - 59) | .------------- hour (0 - 23) | | .---------- day of month (1 - 31) | | | .------- month (1 - 12) OR jan,feb,mar,apr ... | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat | | | | | * * * * * user-name command to be executed
Volume name: The name of the volume on which the scheduled snapshot operation will be performed
For example:
# snap_scheduler.py add "Job1" "* * * * *" test_vol snap_scheduler: Successfully added snapshot schedule
Note
The snapshots taken by the scheduler will have the following naming convention: Scheduler-<Job Name>-<volume name>_<Timestamp>.
For example:
Scheduled-Job1-test_vol_GMT-2015.06.19-09.47.01
Editing a Snapshot Schedule
To edit an existing snapshot schedule, execute the following command:
snap_scheduler.py edit "Job Name" "Schedule" "Volume Name"
where,
Job Name: This name uniquely identifies this particular schedule, and can be used to reference this schedule for future events like edit/delete. If a schedule already exists for the specified Job Name, the add command will fail.
Schedule: The schedules are accepted in the format crond understands. For example:
Example of job definition: .---------------- minute (0 - 59) | .------------- hour (0 - 23) | | .---------- day of month (1 - 31) | | | .------- month (1 - 12) OR jan,feb,mar,apr ... | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat | | | | | * * * * * user-name command to be executed
Volume name: The name of the volume on which the snapshot schedule will be edited.
For Example:
# snap_scheduler.py edit "Job1" "*/5 * * * *" gluster_shared_storage snap_scheduler: Successfully edited snapshot schedule
Listing a Snapshot Schedule
To list the existing snapshot schedule, execute the following command:
snap_scheduler.py list
For example:
# snap_scheduler.py list JOB_NAME SCHEDULE OPERATION VOLUME NAME -------------------------------------------------------------------- Job0 * * * * * Snapshot Create test_vol
Deleting a Snapshot Schedule
To delete an existing snapshot schedule, execute the following command:
snap_scheduler.py delete "Job Name"
where,
Job Name: This name uniquely identifies the particular schedule that has to be deleted.
For example:
# snap_scheduler.py delete Job1 snap_scheduler: Successfully deleted snapshot schedule
