Update Configuration#

Note

We’ll use the normal mode(background) to restart the components. If you want to restart them in daemon mode, please use bash bin/start.sh restart <component> mon. In daemon mode, bin/<component>.pid is the mon pid，bin/<component>.pid.child is the component pid. The mon process is not the system service, if the mon process crashed, the component process becomes the normal background process.

1. Update Nameserver Configuration#

  • Backup configuation

    cp conf/nameserver.flags conf/nameserver.flags.bak

  • Update configuation

  • Restart the nameserver

    bash bin/start.sh restart nameserver

  • Repeat the above steps for the remaining nameservers

2. Update Tablet Configuration#

Here is the impact when update the configuration of tablet:

  • If the table is single-replica, users can choose:

    • add an extra replica before restarting and delete it afterwards (achieved by pre-upgrade and post-upgrade). Then it has the same behavior as the multi-replica case

    • if it is acceptable that the table may be unavailable during the update, users can specify --allow_single_replica during pre-upgrade, which can avoid OOM caused by adding a replica if memory is limited

  • If the table is multi-replica, we will migrate the leader partitions in the tablet to be updating to other tablets, and migrate back after the upgrade. If there is write traffic during the update, there may be data loss.

2.1. Steps of Updating Tablet Configuration#

  • Backup configuation

    cp conf/tablet.flags conf/tablet.flags.bak

  • Update configuation

  • pre-upgrade: to reduce the interruption to the online service before the restart (refer to Operation Tool)

    python tools/openmldb_ops.py --openmldb_bin_path=./bin/openmldb --zk_cluster=172.24.4.40:30481 --zk_root_path=/openmldb --cmd=pre-upgrade --endpoints=127.0.0.1:10921

    If the unavailability of single-replica tables is ok, users can add --allow_single_replica to avoid adding a new replica.

  • Restart tablet

    bash bin/start.sh restart tablet

  • If auto_failover is off, we have to manually recoverdata to restore data.

    python tools/openmldb_ops.py --openmldb_bin_path=./bin/openmldb --zk_cluster=172.24.4.40:30481 --zk_root_path=/openmldb --cmd=recoverdata

  • post-upgrade: revert all the actions done in pre-upgrade

    python tools/openmldb_ops.py --openmldb_bin_path=./bin/openmldb --zk_cluster=172.24.4.40:30481 --zk_root_path=/openmldb --cmd=post-upgrade --endpoints=127.0.0.1:10921

2.2. Confirmation of Restart Result#

  • showopstatus command checks whether there are operations that are kFailed, and check the log to troubleshoot the cause

    python tools/openmldb_ops.py --openmldb_bin_path=./bin/openmldb --zk_cluster=172.24.4.40:30481 --zk_root_path=/openmldb --cmd=showopstatus --filter=kFailed

  • showtablestatus to see if the statuses of all tables are ok

    python tools/openmldb_ops.py --openmldb_bin_path=./bin/openmldb --zk_cluster=172.24.4.40:30481 --zk_root_path=/openmldb --cmd=showtablestatus

After a tablet node is restarted, repeat the above steps for other tablets.

After all tablets are restarted, resume write operations, and run the showtablestatus command to check whether the Rows number has increased.

3. Update APIServer Configuration#

  • Backup configuation

    cp conf/apiserver.flags conf/apiserver.flags.bak

  • Update configuation

  • Restart the apiserver

    bash bin/start.sh restart apiserver

4. Update TaskManager Configuration#

  • Backup configuation

    cp conf/taskmanager.properties conf/taskmanager.properties.bak

  • Update configuation

  • Restart the taskmanager

    bash bin/start.sh restart taskmanager