This section provides guidance on how to manage the Greenplum high availability service, greenplum-postmaster
. The greenplum-postmaster
service monitors the primary segments of a Greenplum cluster to initiate automatic recovery if they become unavailable. This is required if running Greenplum without mirroring. Refer to About the Greenplum Architecture for more information about Greenplum primary segments and mirroring.
Prerequisites
Ensure that you have installed the greenplum-postmaster
service. You may install the greenplum-postmaster
service when you deploy a Greenplum cluster using the Greenplum Virtual Appliance, or by Installing the Greenplum High Availability Service if you deployed your cluster manually.
If you deployed your cluster using the Greenplum Virtual Appliance, the
greenplum-postmaster
service is already enabled and running.If you deployed your cluster manually, the
greenplum-postmaster
service is not enabled by default. Follow Initializing the greenplum-postmaster Service to enable the service.
Validating the Greenplum Postmaster Service
Follow the steps below to check that the greenplum-postmaster
service exists, is enabled, and is running:
- Log in to the master as
gpadmin
. - To check if the service exists and is enabled on all hosts, run:
gpssh -f hosts-all -e 'systemctl --user is-enabled greenplum-postmaster.service'
- To verify that the service is active and running on all hosts, run:
gpssh -f hosts-all -e 'systemctl --user status greenplum-postmaster.service'
Managing the greenplum-postmaster Service
Follow the steps below to stop, start, and view the journal log of the greenplum-postmaster
service:
- Log in to the master as
gpadmin
. - To stop the
greenplum-postmaster
service, run:gpssh -f hosts-all -e 'systemctl --user stop greenplum-postmaster.service'
- To start the
greenplum-postmaster
service, run:gpssh -f hosts-all -e 'systemctl --user start greenplum-postmaster.service'
- To view the journal log, run:
gpssh -f hosts-all -e 'journalctl --user-unit greenplum-postmaster.service'
Troubleshooting
You may encounter an error while accessing journal logs from the gpadmin
user due to insufficient permissions.
$ journalctl --user-unit greenplum-postmaster.service
Hint: You are currently not seeing messages from the system.
Users in the 'systemd-journal' group can see all messages. Pass -q to
turn off this notice.
No journal files were opened due to insufficient permissions.
To resolve the above issue, log in to the master asroot
and run the below command. It will add the gpadmin
user to the systemd-journal
group on all the hosts.
source /usr/local/greenplum-db/greenplum_path.sh
gpssh -f /home/gpadmin/hosts-all -e 'usermod -a -G systemd-journal gpadmin'
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