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Clarify format of service environment variables. Fixes #1936.

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Brian Grant 2014-11-24 18:01:56 +00:00
parent 248dddf34a
commit e448604c7f
1 changed files with 15 additions and 2 deletions
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docs/services.md
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@ -62,8 +62,21 @@ according to a policy, but the only policy supported for now is round-robin).
When a `pod` is scheduled, the master adds a set of environment variables for
each active `service`. We support both
[Docker-links-compatible](https://docs.docker.com/userguide/dockerlinks/)
variables and simpler {SVCNAME}_SERVICE_HOST and {SVCNAME}_SERVICE_PORT
variables. This does imply an ordering requirement - any `service` that a `pod`
variables (see [makeLinkVariables](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/pkg/kubelet/envvars/envvars.go#L49)) and simpler {SVCNAME}_SERVICE_HOST and {SVCNAME}_SERVICE_PORT
variables, where the service name is upper-cased and dashes are converted to underscores.
For example, the service "redis-master" exposed on TCP port 6379 and allocated IP address
10.0.0.11 produces the following environment variables:
```
REDIS_MASTER_SERVICE_HOST=10.0.0.11
REDIS_MASTER_SERVICE_PORT=6379
REDIS_MASTER_PORT=tcp://10.0.0.11:6379
REDIS_MASTER_PORT_6379_TCP=tcp://10.0.0.11:6379
REDIS_MASTER_PORT_6379_TCP_PROTO=tcp
REDIS_MASTER_PORT_6379_TCP_PORT=6379
REDIS_MASTER_PORT_6379_TCP_ADDR=10.0.0.11
```
This does imply an ordering requirement - any `service` that a `pod`
wants to access must be created before the `pod` itself, or else the environment
variables will not be populated. This restriction will be removed once DNS for
`services` is supported.