Qiming
b8fb58f333
We have been using redirections in many pages when referencing the API docs generated. Since the relocation of the generated files, this is becoming difficult to maintain. This PR redirects all such links to the generated artifacts so we can easily detect missing links if any. closes: #7874
83 lines
2.3 KiB
Markdown
83 lines
2.3 KiB
Markdown
---
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title: Define Environment Variables for a Container
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---
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{% capture overview %}
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This page shows how to define environment variables when you run a container
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in a Kubernetes Pod.
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{% endcapture %}
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{% capture prerequisites %}
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{% include task-tutorial-prereqs.md %}
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{% endcapture %}
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{% capture steps %}
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## Define an environment variable for a container
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When you create a Pod, you can set environment variables for the containers
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that run in the Pod. To set environment variables, include the `env` or
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`envFrom` field in the configuration file.
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In this exercise, you create a Pod that runs one container. The configuration
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file for the Pod defines an environment variable with name `DEMO_GREETING` and
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value `"Hello from the environment"`. Here is the configuration file for the
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Pod:
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{% include code.html language="yaml" file="envars.yaml" ghlink="/docs/tasks/inject-data-application/envars.yaml" %}
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1. Create a Pod based on the YAML configuration file:
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kubectl create -f https://k8s.io/docs/tasks/inject-data-application/envars.yaml
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1. List the running Pods:
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kubectl get pods -l purpose=demonstrate-envars
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The output is similar to this:
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NAME READY STATUS RESTARTS AGE
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envar-demo 1/1 Running 0 9s
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1. Get a shell to the container running in your Pod:
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kubectl exec -it envar-demo -- /bin/bash
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1. In your shell, run the `printenv` command to list the environment variables.
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root@envar-demo:/# printenv
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The output is similar to this:
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NODE_VERSION=4.4.2
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EXAMPLE_SERVICE_PORT_8080_TCP_ADDR=10.3.245.237
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HOSTNAME=envar-demo
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...
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DEMO_GREETING=Hello from the environment
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DEMO_FAREWELL=Such a sweet sorrow
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1. To exit the shell, enter `exit`.
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**Note:** The environment variables set using the `env` or `envFrom` field
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will override any environment variables specified in the container image.
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{: .note}
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{% endcapture %}
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{% capture whatsnext %}
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* Learn more about [environment variables](/docs/tasks/configure-pod-container/environment-variable-expose-pod-information/).
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* Learn about [using secrets as environment variables](/docs/user-guide/secrets/#using-secrets-as-environment-variables).
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* See [EnvVarSource](/docs/reference/generated/kubernetes-api/{{page.version}}/#envvarsource-v1-core).
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{% endcapture %}
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{% include templates/task.md %}
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