Upgrade#

Here is the impact when upgrading OpenMLDB:

If the table is single-replica, users can choose:
- add an extra replica before upgrading 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 upgrade, 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 upgraded to other tablets, and migrate back after the upgrade. If there is write traffic during the upgrade, there may be data loss.

Note

We’ll use the normal mode(background) to start the components. If you want to start them in daemon mode, please use bash bin/start.sh start <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. Upgrade Nameserver#

Stop nameserver
```
bash bin/start.sh stop nameserver
```
Backup the old bin directory
Replace with the new bin
Start the new nameserver
```
bash bin/start.sh start nameserver
```
Repeat the above steps for the remaining nameservers

2. Upgrade Tablets#

2.1. Steps of Upgrading Tablets#

pre-upgrade: to reduce the interruption to the online service before the upgrade (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.
Stop tablet
```
bash bin/start.sh stop tablet
```
Backup the old bin directory
Replace with the new bin
Start tablet
```
bash bin/start.sh start 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 Upgrade 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 upgraded, repeat the above steps for other tablets.

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

3. Upgrade APIServer#

Stop apiserver
```
bash bin/start.sh stop apiserver
```
Backup the old bin directory
Replace with the new bin directory
Start the new apiserver
```
bash bin/start.sh start apiserver
```

4. Upgrade Taskmanager#

Upgrade OpenMLDB Spark Distribution: download the new version of spark distribution and replace with the old one located in $SPARK_HOME
Stop taskmanager
```
bash bin/start.sh stop taskmanager
```
Backup the old bin and taskmanager directories
Replace with the new bin and taskmanager directories
Start the new taskmanager
```
bash bin/start.sh start taskmanager
```

5. Upgrade the SDKs#

Upgrade Java SDK#

Update the java sdk version number in the pom file, including openmldb-jdbc and openmldb-native

Upgrade Python SDK#

install the new python sdk
```
pip install openmldb=={NEW_VERSION}
```