This section describes the operation of a9s Parachute component.
The a9s Parachute is intended to ensure that certain services are stopped properly in the event of a disk filling up, in order to prevent data loss. For this purpose, the a9s Parachute runs on every a9s Data Service instance. The a9s Parachute monitors both the ephemeral and the persistent disk and as soon as the disk usage exceeds a configured threshold, the a9s Parachute stops the configured services.
The a9s Parachute can be configured via the following BOSH properties:
|80||Limit in percent for the ephemeral disk usage. |
|80||Limit in percent for the persistent disk usage. |
|An array with the names of the |
To make the a9s Parachute observable, the following lock files are created in
/var/vcap/sys/run/a9s-parachute directory on the VM of the respective
node of the service instance when the a9s Parachute is triggered:
a9s-parachute-activated: Indicates that the a9s Parachute has been triggered and the configured services have been stopped
a9s-parachute-activated-ephemeral: Indicates that the a9s Parachute for the ephemeral disk has been triggered
a9s-parachute-activated-persistent: Indicates that the a9s Parchute for the persistent disk has been triggered
Keep in mind, if the a9s Parachute wasn't triggered the above file will not
exist and the directory
/var/vcap/sys/run/a9s-parachute will be empty.
Manually Restart a Service Instance’s Node
To manually restart the processes of a service instance's node and re-enable the a9s Parachute so that it stops the configured processes again when a disk fills up, the following steps are necessary:
- SSH into the affected node of the service instance via `bosh -d <deployment_name> ssh <instance_name>
- Become root via
- Remove all a9 Parachute lock files via
rm -rf /var/vcap/sys/run/a9s-parachute
- Enable the a9s Parachute checks via
monit start ephemeraland
monit start persistent
- Start the stopped processes via
monit start <process_name>
Keep in mind that the a9s Parachute doesn't clear up disk space, so you have to free up the disk space manually.
For more information, see a9s Parachute Resources Considerations.