Best practices for running API management in Docker containers

3 minute read

Reduce Docker image size

The API Gateway Docker image created with the standard Docker sample scripts has a considerable size. Follow these steps to reduce the size of the image by around 200 MB.

The scripts are provided as an example and you can adjust them as needed for your requirements.

Reduce the size of base images

To remove files and folders which are not required in the base images:

1. Download the Docker samples (APIGateway_7.7.YYYYMMDD-<bn>_DockerScripts.tar.gz) and extract the package.

2. In the extracted package open the file Dockerfiles/gateway-base/scripts/runInstall.sh.

3. Add a line starting with rm -rf to remove any files you do not require from the image. For example:

   # removes some sample McAfee DAT files  
   /opt/Axway/apigateway/conf/plugin
   # removes the IBM-MQ driver, which might not be required in your environment  
   /opt/Axway/apigateway/system/lib/ibmmq
   # Database setup scripts not required as part of the Docker container  
   /opt/Axway/apigateway/system/conf/sql
   # Not required MIB description  
   /opt/Axway/apigateway/system/conf/snmp
   # Policy configuration templates not required as part of the Docker container  
   /opt/Axway/apigateway/system/conf/templates/*
   # Sample SpiderLabs Mod-Security pattern  
   /opt/Axway/apigateway/system/conf/threat-protection/SpiderLabs-owasp-modsecurity-crs-2.2.9-7-g3e6782b.zip
   # Gateway Metrics plugin for Oracle Enterprise Manager also not required  
   /opt/Axway/apigateway/system/conf/oracle-em
   # Configuration migration artifacts  
   /opt/Axway/apigateway/system/conf/migrate
   # Provided samples not required as part of the Docker container  
   /opt/Axway/apigateway/samples
   # If you don't need the SDK-Generator you can remove it as well  
   /opt/Axway/apigateway/tools/sdk-generator
   

   Download runInstall.sh for a complete example.

   It is best to version control any changes you make in the file.

After these changes, the size of the generated Docker base images is reduced from 947MB to 747MB.

Optimize images for Node Manager and API Gateways

In addition, you can create a layered multi-stage image for API Gateway and Admin Node Manager, and you can remove additional folders, which are not required, from these images. For example, follow this procedure to reduce the size of the API Gateway image to 715 MB and the Admin Node Manager image to 708 MB.

1. Open the file Dockerfiles/emt-nodemanager/Dockerfile.

2. Change the line FROM $PARENT_IMAGE to FROM $PARENT_IMAGE as base.

3. Add the following line at the end of the file, before the CMD instruction:

   FROM centos:7
   COPY --from=base /opt/Axway/apigateway /opt/Axway/apigateway
   

4. Remove any folder which is not required.

Download the following complete example files to learn which folders you can remove in each image:

• anm-dockerfile
• gw-dockerfile

Set local environment variables

The API Gateway Docker image is automatically created with the LANG environment variable set to en_US.UTF-8. This is required to handle Unicode-named files that might be in use in your configuration (fed files). If needed, this environment variable can be manually overridden in two ways:

• By editing the API Gateway Dockerfile, found at Dockerfiles\emt-gateway\Dockerfile. Change or remove the line ENV LANG=en_US.UTF-8 to modify this environment variable.

• By overriding the image default environment variable while running an API Gateway Docker container. For example:

  docker run -d --name=apimgr --network=api-gateway-domain -p 8075:8075 -p 8065:8065 -p 8080:8080 -v /tmp/events:/opt/Axway/apigateway/events -e EMT_ANM_HOSTS=anm:8090 -e     CASS_HOST=casshost1 -e METRICS_DB_URL=jdbc:mysql://metricsdb:3306/metrics?useSSL=false -e METRICS_DB_USERNAME=db_user1 -e METRICS_DB_PASS=my_db_pwd -e EMT_TRACE_LEVEL=DEBUG     api-gateway-my-group:1.0 -e LANG=en_IE.UTF-8