Docker issues
During the application of a patch, you may run into a situation where a Docker container fails to start or remains in restarting mode in a loop. There are multiple reasons why this may occur; however, common cases are as follows.
Docker Service failure
In this case, try to restart the Docker Service and monitor the Docker Service logs. Instructions on how to monitor the Docker Service logs can be found here:
https://docs.docker.com/engine/reference/commandline/service_logs/
Often, logging out and relogging in the current user can also fix the Docker Service or any command availability related issues.
Docker image entry-point resources are unavailable
If this occurs, stop the Docker container. Then, try to start a new container with a different entry-point, using the following command:
docker run -it --entrypoint /bin/bash <image id>
This command will start the container and will skip the image’s default entry-point execution. This should eliminate the execution of any resource access issues that were occurring during the execution of the default entry-point. At this point, you can then look at the entry-point’s implementation and try to understand what may have caused the issue. Note that this approach will not fix the issue, but it will provide you with an effective method of analysis to find the issue’s root cause.
Docker container corruption
You may potentially run into a situation where a Docker container becomes corrupted or damaged. In this case, you can purge the damaged container and start a new one.
To initialize a brand new Docker container, run the following commands:
- Purge existing container
docker rm -f <container name or id> - Create a container
Web/Application Server: <dqplus home>/bin/startApplicationPostgres/Application DB: <dqplus home>/bin/startApplicationDbNGINX/Load Balancer: <dqplus home>/bin/startLoadBalancer