Uninstalling the openGauss

The process of uninstalling the openGauss includes uninstalling the openGauss and clearing the environment of the openGauss server.

Executing Uninstallation

The openGauss provides an uninstallation script to help users uninstall the openGauss.

Procedure

Log in as the OS user omm to the primary node of the database.
Execute the gs_uninstall script to uninstall the openGauss.
```
gs_uninstall --delete-data
```
Alternatively, locally uninstall each node of the openGauss.
```
gs_uninstall --delete-data -L
```

Examples

Execute the gs_uninstall script to uninstall the openGauss.

gs_uninstall --delete-data
Checking uninstallation.
Successfully checked uninstallation.
Stopping the cluster.
Successfully stopped the cluster.
Successfully deleted instances.
Uninstalling application.
Successfully uninstalled application.
Uninstallation succeeded.

Execute the gs_uninstall script to perform single-node uninstallation.

gs_uninstall --delete-data
Checking uninstallation.
Successfully checked uninstallation.
Stopping the cluster.
Successfully stopped the cluster.
Successfully deleted instances.
Uninstalling application.
Successfully uninstalled application.
Uninstallation succeeded.

Troubleshooting

If the uninstallation fails, locate faults by following the log information provided in the $GAUSSLOG/om/gs_uninstall-YYYY-MM-DD_HHMMSS.log file.

Deleting Cluster Configurations

After the openGauss is uninstalled, execute the gs_postuninstall script to delete configurations from all servers in the openGauss if you do not need to re-deploy the openGauss using these configurations. These configurations are made by the gs_preinstall script.

Prerequisites

The openGauss uninstallation task has been successfully executed.
User root is trustworthy and available.
Only user root is authorized to run the gs_postuninstall command.

Procedure

Check whether the mutual trust has been established between the users root. If not, manually establish the mutual trust. For details, see Establishing Mutual Trust Manually.

Run the ssh Host name command to check whether mutual trust has been successfully established. Then, enter exit.

plat1:~ # ssh plat2 
Last login: Tue Jan  5 10:28:18 2016 from plat1 
Huawei's internal systems must only be used for conducting Huawei's business or for purposes authorized by Huawei management.Use is subject to audit at any time by Huawei management. 
plat2:~ # exit 
logout 
Connection to plat2 closed. 
plat1:~ #

Go to the following path:
```
cd /opt/software/openGauss/script
```
Run the gs_postuninstall command to clear the environment. If the cluster is installed in environment variable separation mode, run the source command to obtain the environment variable separation file ENVFILE.
```
./gs_postuninstall -U omm -X /opt/software/openGauss/cluster_config.xml --delete-user --delete-group
```
Alternatively, locally use the gs_postuninstall tool to clear each openGauss node.
```
./gs_postuninstall -U omm -X /opt/software/openGauss/cluster_config.xml --delete-user --delete-group -L
```
omm is the name of the OS user who runs the openGauss, and the path of the openGauss configuration file is /opt/software/openGauss/cluster_config.xml.
If the cluster is installed in environment variable separation mode, delete the environment variable separation parameter ENV obtained by running the source command.
unset MPPDB_ENV_SEPARATE_PATH
Delete the mutual trust between the users root on each openGauss database node.
Log out the root user.

Examples

Clear the host environment.

gs_postuninstall -U omm -X /opt/software/openGauss/cluster_config.xml --delete-user
Parsing the configuration file.
Successfully parsed the configuration file.
Check log file path.
Successfully checked log file path.
Checking unpreinstallation.
Successfully checked unpreinstallation.
Deleting Cgroup.
Successfully deleted Cgroup.
Deleting the instance's directory.
Successfully deleted the instance's directory.
Deleting the installation directory.
Successfully deleted the installation directory.
Deleting the temporary directory.
Successfully deleted the temporary directory.
Deleting remote OS user.
Successfully deleted remote OS user.
Deleting software packages and environmental variables of other nodes.
Successfully deleted software packages and environmental variables of other nodes.
Deleting logs of other nodes.
Successfully deleted logs of other nodes.
Deleting software packages and environmental variables of the local node.
Successfully deleted software packages and environmental variables of the local nodes.
Deleting local OS user.
Successfully deleted local OS user.
Deleting local node's logs.
Successfully deleted local node's logs.
Successfully cleaned environment.

Troubleshooting

If the configuration deletion fails, locate faults by following the log information provided in the $GAUSSLOG/om/gs_postuninstall-YYYY-MM-DD_HHMMSS.log file.