{"pageProps":{"article":{"slug":"how-to-use-configmaps-in-kubernetes","title":"How to Use ConfigMaps in Kubernetes","description":"Learn how to use ConfigMaps in Kubernetes with some examples.","content":"\nWhen starting to use a new technology, one of the first questions to answer is how to manage your application's configuration. In the Kubernetes world, that answer is ConfigMaps.\n\nWith this article, you'll learn how to use them.\n\n# What is a ConfigMap?\n\nA ConfigMap is a dictionary composed of by a key-value pairs of strings.\nIt basically stores (public) configuration settings for your code. If you want to store secret configuration settings, you'll need to store them in another manner.\n\n# How ConfigMaps are deployed\n\n1. You have ConfigMap/s for every environment.\n2. A ConfigMap is created and added to a Kubernetes cluster.\n3. Containers in a Pod reference the ConfigMap to use its values.\n\n# Optimal way to create and mount a ConfigMap\n\nFor me the best way to use ConfigMaps is defining a YAML and reference them using `envFrom/configMapRef`.\n\n## Here is an example of a ConfigMap in a YAML file\n\n```yaml\nkind: ConfigMap\napiVersion: v1\nmetadata:\n  name: env-vars-configmap\n  namespace: my-namespace\ndata:\n  # Configuration values as key-value properties where value is a string\n  base_url: https://my.website.dev/\n  database_port: \"3306\"\n\n  # Also you can read those values from variables\n  base_url: ${BASE_URL}\n  database_port: \"${DATABASE_PORT}\"\n\n  # Or set as file contents\n  file_keys: |\n    color.good=purple\n    color.bad=yellow\n```\n\nTo added it to your namespace in the Kubernetes cluster:\n\n```bash\n$ kubectl apply -f env-vars-configmap.yaml -n my-namespace\n```\n\nAlso you can see the values of the environment variables executing:\n\n```bash\n$ kubectl get configmap -n my-namespace env-vars-configmap.yaml -o yaml\n```\n\n_Tip: this last command is useful when you have errors in the ConfigMap. If you use variables, try replace them with the real values and see which one fails._\n\n## Reference the ConfigMap\n\nSet the `envFrom/configMapRef` in each container to an object containing the list of ConfigMaps you want to include.\n\n```yaml\nkind: Pod\napiVersion: v1\nmetadata:\n  name: pod-configmap\n  namespace: my-namespace\nspec:\n  containers:\n    - name: my-container\n      image: nginx:1.7.9\n      envFrom:\n        - configMapRef:\n            name: env-vars-configmap\n```\n\nAttach to the created Pod using:\n\n```bash\n$ kubectl exec -it pod-configmap sh\n```\n\nThen run `env` and see that all keys are now available as environment variables.\n\nFor more information related to ConfigMaps, please check the [Kubernetes documentation](https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/).\n","type":"article","tags":["code","kubernetes","k8s","configmap"],"publishedAt":"2020-04-13T11:11:11.915Z","image":"https://boxboat.com/2018/07/05/gitops-kubernetes-rolling-update-configmap-secret-change/kube-configmap-secret-deployment.png","updatedAt":"2020-05-09T14:56:10.915Z","readingTime":{"text":"2 min read","minutes":1.79,"time":107400,"words":358},"data":{"title":"How to Use ConfigMaps in Kubernetes","description":"Learn how to use ConfigMaps in Kubernetes with some examples.","tags":["code","kubernetes","k8s","configmap"],"image":"https://boxboat.com/2018/07/05/gitops-kubernetes-rolling-update-configmap-secret-change/kube-configmap-secret-deployment.png","publishedAt":"2020-04-13T11:11:11.915Z","updatedAt":"2020-05-09T14:56:10.915Z","type":"article"}},"prev":{"slug":"how-to-use-secrets-in-kubernetes","title":"How to Use Secrets in Kubernetes","description":"Learn how to use Secrets in Kubernetes with some examples.","content":"\nKubernetes Secrets let you store and manage sensitive information like as passwords, OAuth tokens, ssh keys, etc. \n\nWith this article, you'll learn how to use them easily.\n\n# What is a Secret in Kubernetes?\n\nA secret is an object that contains sensitive information like passwords, keys, tokens...\n\nTo use it, a Pod needs to reference it:\n* As files in a volume mounted on one or more of its containers.\n* By the `kubelet` when pulling images for the Pod.\n\n# Optimal way to create and mount a Secret\n\nFor me the easiest way to use Secrets is defining a YAML and reference them using `envFrom/secretRef`.\n\n1. Here is a yaml configuration file you can use to create a Secret that holds a username and a password:\n\n```yaml\napiVersion: v1\nkind: Secret\nmetadata:\n  name: my-secret\ndata:\n  username: my-username\n  password: vdg7JbgkdnRnN03e\n```\n\n2. Reference the Secret (my-secret-pod.yaml):\n\n```yaml\nkind: Pod\napiVersion: v1\nmetadata:\n  name: my-secret-pod\n  namespace: my-namespace\nspec:\n  containers:\n    - name: my-container\n      image: nginx:1.7.9\n      envFrom:\n        - secretRef:\n            name: my-secret\n```\n\n3. Then you just need to create the Pod:\n\n```bash\n$ kubectl apply -f my-secret-pod.yaml -n my-namespace\n```\n\nFor more information related to Secrets, please check the [Kubernetes documentation](https://kubernetes.io/docs/tasks/inject-data-application/distribute-credentials-secure/).\n","type":"article","tags":["code","kubernetes","k8s","secret"],"publishedAt":"2020-04-18T10:10:10.915Z","image":null,"updatedAt":"2020-04-18T11:27:10.915Z","readingTime":{"text":"1 min read","minutes":0.99,"time":59400,"words":198},"data":{"title":"How to Use Secrets in Kubernetes","description":"Learn how to use Secrets in Kubernetes with some examples.","tags":["code","kubernetes","k8s","secret"],"publishedAt":"2020-04-18T10:10:10.915Z","updatedAt":"2020-04-18T11:27:10.915Z","type":"article"}},"next":{"slug":"for-whom-is-this-blog-for","title":"For Whom Is This Blog For?","description":"Learn about this blog and if it's for you.","content":"\nAs developers, we are learning new things every day.\n\nIn this blog I want to share what I'm currently learning, but also what I've learned.\n\nSo if you want to know more about the development of APIs and machine learning, from a developer with more than 10 years of experience, please follow me on Twitter, subscribe to my newsletter or to my RSS feed.\n\nSpecial thank you to Lailo and his [open source code](https://github.com/lailo/next-with-tailwindcss) that I used for this blog.\n","type":"article","tags":["blog","ml","code","api"],"publishedAt":"2020-03-29T07:07:37.915Z","image":null,"updatedAt":"2020-04-18T11:18:10.915Z","readingTime":{"text":"1 min read","minutes":0.4,"time":24000,"words":80},"data":{"title":"For Whom Is This Blog For?","description":"Learn about this blog and if it's for you.","tags":["blog","ml","code","api"],"publishedAt":"2020-03-29T07:07:37.915Z","updatedAt":"2020-04-18T11:18:10.915Z","type":"article"}}},"__N_SSG":true}