We could set up environment variables to configure this image. Most of them are defined in [backend-setup](https://github.com/apache/skywalking/blob/v6.1.0/docs/en/setup/backend/backend-setup.md), but Apache SkyWalking Docker Image adds extra environment variables to help the user to compose it properly. The details are located in [docker-entrypoint.sh](docker-entrypoint.sh)
## SW_CLUSTER
Default value is `standalone`, avaliable values are:
-`standlone`, If set this value, all enviroment variables of `cluster.standlone` in `application.yml` are avaliable.
-`zookeeper`, If set this value, all enviroment variables of `cluster.zookeeper` in `application.yml` are avaliable.
-`kubernetes`, If set this value, all enviroment variables of `cluster.kubernetes` in `application.yml` are avaliable.
-`consul`, If set this value, all enviroment variables of `cluster.consul` in `application.yml` are avaliable.
## SW_STORAGE
Default value is `H2`, avaliable values are:
-`H2`, If set this value, all enviroment variables of `storage.h2` in `application.yml` are avaliable.
-`elasticsearch`, If set this value, all enviroment variables of `stroage.elasticsearch` in `application.yml` are avaliable.
-`mysql`, If set this value, all enviroment variables of `stroage.mysql` in `application.yml` are avaliable.
## XXX_ENABLED
There are also some other configuration switchers to extend default configuration, they also have a suffix `_ENABLED`.