README
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Perímener ✋
Named after the Greek word Perímene αναμονή for wait.
A golang application that waits for the expected number of pods to reach a Ready state before gracefully exiting.
Problem statement
Have you ever needed an initContainer which can perform simple dependency management.
Starting containers before their dependencies are ready can result in pods going into a status of CrashLoopBackoff these wastes resources which could have been used on the dependencies themselves.
An example of this might be ensuring that a number of zookeeper pods reach a Ready state before kafka is started.
Perímener also has functionality to avoid the thundering herd issue which is amplified when using GitOps principles.
Setting an environment variable inserts a random delay from 0 to <RANDOM_WINDOW_SECONDS> to application startup which can help prevent undesirable autoscaling events.
Usage
Configuration is done via the use of ENVIRONMENT variables
| Environment variable Name | Parameter Function | Required/Default |
|---|---|---|
| DELAY_SECONDS | Delay start of the main container by n seconds | Default: 0 seconds (Disabled) |
| EXPECTED_READY_POD_COUNT | The number of pods to reach a Ready state before the init container will exit and allow the main container to start |
Required |
| NAMESPACE | Which namespace to target | Required |
| POD_LABEL | A label selector which matches the required pods | Required |
| RANDOM_WINDOW_SECONDS | Max seconds for window size | Default: 0 seconds (Disabled) |
| SLEEP_COUNT | The time to wait between retries | Default: 5 seconds |
| USE_LOCAL_KUBECONFIG | Use a local kubeconfig or not. Defaults to in cluster auth | Default: false |
Documentation
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There is no documentation for this package.
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