Category Archives: Kubernetes secrets and configmaps

Kubernetes secrets and configmaps

ConfigMaps are a useful Kubernetes feature that allows you to maintain light portable images by separating the configuration settings. Using small layered images is one of the practices for building efficient Kubernetes clusters. Utilizing ConfigMaps can help you achieve that.

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ConfigMaps are APIs that store configuration data in key-value pairs. Their primary function is to keep the configuration separate from the container image. It can represent the entire configuration file or individual properties. If you are working with Kubernetes, you want to keep your image light and portable. To do this, you should keep the configuration settings separate from the application code.

Using ConfigMaps you can add different configuration data on pods to suit the environment they are running in. For example, you may use the same code with different configuration while in the development, testing or production phase. To store and manage sensitive information, use Kubernetes Secrets. Use a. For example, to create a ConfigMap under the name example-configmap from the example-configmap. Kubernetes allows creating a ConfigMap from one or multiple files in any plaintext format as long as the files contain key-value pairs.

You can also create ConfigMaps from directories, that is from all the files within the directory. To do so, use the command:.

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Kubectl packages each file from the directory into the new ConfigMap. Only files with basenames that are valid keys are included. Subdirectories and non-regular files are not included in the ConfigMap.

You can also create ConfigMaps from literal values, using the --from-literal option. Once you have downloaded or created a ConfigMap, you can mount the configuration to the pod by using volumes.

Once you have added the required content, use the kubectl create command to create the pod with the ConfigMap as the volume. Add the env section to the yaml file of the pod to pull the specified environment variable s from a ConfigMap:.

To pull all environment variables from a ConfigMap, add the envFrom section to the yaml file:. Then, use the kubectl create command to create the pod with the specified configuration settings.Up until now the deployment template has included all of the configuration required by pod containers. This is a big improvement over storing the configuration inside the binary or container image which makes it difficult to reuse. Having configuration in the pod spec also makes it less portable.

Furthermore, if the configuration involves sensitive information such as passwords or API keys, then it also presents a security issue. This separation makes it easier to manage and change configuration. It also makes for more portable manifests.

ConfigMaps and secrets are very similar and used in the same way when it comes to pods. One difference is that secrets are specifically for storing sensitive information. Secrets reduce the risk of their data being exposed. However the cluster administrator also needs to ensure all the proper encryption and access control safeguards are in place to really consider secrets being safe.

Pods can use the data by mounting them as files by using a volume or as environment variables. I will show examples of these in the demo. Now, lets look at how the ConfigMap manifest looks:.

First notice there is no spec, rather the key-value pairs that the ConfigMap stores are under a mapping named data. Here we have a single key named config.


You can have more than one but one is enough for our purpose. The value of config is a multi-line string that represents the file contents of a redis configuration file. The bar or pipe symbol after config is YAML for starting a multi-line string and causes all of the following lines to be the value of config including the Redis config comment.

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The configuration file values set the tcp keepalive and maxmemory of redis. These are arbitrarily chosen for this example.

kubernetes secrets and configmaps

Separating the configuration makes it easy to manage configuration separately from the pod spec. We will have to make some initial changes to the pod to make use of the ConfigMap but after that the two can be managed separately.

Starting from the volumes, a new ConfigMap type of volume is added and it references the redis-config ConfigMap we just saw. Items declares which key value pair we want to use from the config map. We only have one in our case and that is config. If you have multiple environments, you could easily do things like referencing a dev configuration in one environment and a production configuration in another.

The path sets the path of the file that will be mounted with the config value. This is relative to the mount point of the volume.

Kubernetes ConfigMap Tutorial with Examples

The last change that we need is to use a custom command for the container so that redis knows to load the config file when it starts. With this setup we can now independently configure redis without touching the deployment template. As a quick sidenote before we create the resources, if we were dealing with a secret rather than a configmap the volume type would be secret rather than configMap and the name key would be replaced with secretName. Everything else would be the same.

See that the contents match the configmap value that we specified. Now to prove that redis actually loaded the config we can output tcp-keepalive configuration value to make sure it matches the value in the file. And there we have it. Separation of configuration and pod spec is complete. Before we move on I want to highlight how changes to configmaps interact with volumes and deployments.Join Stack Overflow to learn, share knowledge, and build your career. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

kubernetes secrets and configmaps

In general, we like intent-based APIs, and the intent is definitely different for secret data vs. Both, ConfigMaps and Secrets store data as a key value pair. The major difference is, Secrets store data in base64 format meanwhile ConfigMaps store data in a plain text. If you have some critical data like, keys, passwords, service accounts credentials, db connection string, etc then you should always go for Secrets rather than Configs.

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Learn more. Asked 4 years, 9 months ago. Active 17 days ago. Viewed 17k times. Have been using Kubernetes secrets up to date. Now we have ConfigMaps as well. What is the preferred way forward - secrets or config maps? After a few iterations we have stabilised at the following rule: configMaps are per solution domain can be shared across microservices within the domain, but ultimately are single purpose config entries secrets are shared across solution domains, usually represent third party systems or databases.

kubernetes secrets and configmaps

Evgeny Minkevich. Evgeny Minkevich Evgeny Minkevich 1, 2 2 gold badges 21 21 silver badges 34 34 bronze badges. Active Oldest Votes. I'm the author of both of these features.

Hope that helps. Andrzej Sydor 1, 2 2 gold badges 9 9 silver badges 18 18 bronze badges. Paul Morie Paul Morie In this blog, we will explore how we can use the the configuration data like database details using Config Maps and Secrets.

There is no change from the application, application remains the same in all the environments. The only thing which will change is the database details. So we need to make our application code in such a way that we can provide the environment specific data separately. Kubernetes provides to associate environment-specific data with our application containers without changing our container image.

You can see both configMaps are showing Data as 1 but in our file we have defined two keys. Note that the name of the file, application. The name field under the volume and volumeMounts sections has to be the same so that Kubernetes can identify which volume is associated with which volumeMounts.

Notify me of follow-up comments by email. Notify me of new posts by email. Skip to content. Config Map Used to define application-related data It decouples the application data from the application so that the same application can be ported across different environments.

NOTE: The name field under the volume and volumeMounts sections has to be the same so that Kubernetes can identify which volume is associated with which volumeMounts.

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Run kubectl create -f pod-configMap-mount. Leave a Reply Cancel reply Your email address will not be published. Comment Name Email Website Notify me of follow-up comments by email.Learn why leading companies have migrated from OpenShift to Giant Swarm and experience faster time-to-market, higher productivity of their devops teams, better security and cost savings. Get a first impression of the world's most powerful Kubernetes platform managed inside your private and public cloud environments.

Learn how Vodafone created a blueprint for cloud-native projects and how Giant Swarm has become the foundation for their most critical digital initiatives. Learn everything you need to know about the choices and best-practices for all key components you need to consider to build your cloud-native platform. At Giant Swarm, everything we do is intertwined with our values.

The decision to take our roadmap public is no exception. We began by challenging the status quo.

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Our roadmap has always resided in our private GitHub repository. This post is the fourth in a series of blog posts about basic Kubernetes concepts. In the second post we talked about Deployments. The third post explained the Services concept and now we will look at Secrets and ConfigMaps. In the fifth and final post we talk about Daemon Sets and Jobs. The third factor of the 12 factor app methodology is called Config and describes why you should store configuration in the environment.

Thus, you should store the config outside of the application itself. Now with Docker and containers this means we should try to keep configuration out of the container image. This is even more needed when working with sensitive information, such as passwords, keys, auth tokens, because we might not want them to be available in a registry, even if that registry might be private.

In Docker we would use --env or --env-file for this no matter if we are working with sensitive information or just plain configuration. In Kubernetes we have two separate primitives for these use cases. The first is Secretswhich as the name suggest is for storing sensitive information. The second one is ConfigMapswhich you can use for storing general configuration.

Kubernetes ConfigMap and Secret as Kubernetes Volumes - Demo

The two are quite similar in usage and support a variety of use cases. Secrets can and should be used for storing small amounts less than 1MB each of sensitive information like passwords, keys, tokens, etc. Kubernetes creates and uses some secrets automatically e. Using secrets is quite straightforward. You reference them in a pod and can then use them either as files from volumes or as environment variables in your pod.

Keep in mind that each container in your pod that needs to access the secret needs to request it explicitly. Using these you can pass a Docker or other container image registry login to the Kubelet, so it can pull a private image for your pod. You need to explicitly update your pods for example using the rolling update functionality of deployments explained in the second blog post in this series. Further keep in mind that you create a secret in a specific namespace and only pods in the same namespace can access the secret.

Secrets are kept in a tmpfs and only on nodes that run pods that use those secrets. The tmpfs keeps secrets from coming to rest on the node. ConfigMaps are similar to Secrets, only that they are designed to more conveniently support working with strings that do not contain sensitive information.Today I want to talk about why I wrote k8s secret sync operator and how did I Code it.

We can copy secrets and configmaps when we have a couple of namespaces and secrets. But when we have dozens of namespaces, it can be very complicated. Because of that, I wrote a small Kubernetes Operator with python and Kopf. The name of the project is Synator, which I shared as open source on Github, you can view here. I wanted to choose an easy framework for writing the K8s operator for the first time. Kopf is perfect for this. Helm documentation is very good and very easy to use.

All we have to do is deploy deploy. ServiceAccount and ClusterRole are required to communicate with the Kubernetes API, which generates tokens for us and inject them directly into the pod. Finally, I want to talk about the feature I added. Restart the pod when the secret or ConfigMap is refreshed. Thank you for reading my article. Have a nice work day. Sign in.


Kubernetes Secret and Configmap sync. Kaan Karakaya Follow. Written by Kaan Karakaya Follow. More From Medium. Hardening Docker and Kubernetes with seccomp.

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About Help Legal.Kubernetes v1. The version you are currently viewing is a static snapshot. For up-to-date documentation, see the latest version. Edit This Page. Pods A Pod represents a set of running containers in your cluster. A ConfigMap allows you to decouple environment-specific configuration from your container images Stored instance of a container that holds a set of software needed to run an application. For example, imagine that you are developing an application that you can run on your own computer for development and in the cloud to handle real traffic.

Locally, you set that variable to localhost. In the cloud, you set it to refer to a Kubernetes Service A way to expose an application running on a set of Pods as a network service.

This lets you fetch a container image running in the cloud and debug the exact same code locally if needed. Unlike most Kubernetes objects that have a speca ConfigMap has a data section to store items keys and their values. You can write a Pod spec that refers to a ConfigMap and configures the container s in that Pod based on the data in the ConfigMap. The Pod and the ConfigMap must be in the same namespace An abstraction used by Kubernetes to support multiple virtual clusters on the same physical cluster.

Here's an example ConfigMap that has some keys with single values, and other keys where the value looks like a fragment of a configuration format. There are four different ways that you can use a ConfigMap to configure a container inside a Pod:. These different methods lend themselves to different ways of modeling the data being consumed. For the first three methods, the kubelet An agent that runs on each node in the cluster.

It makes sure that containers are running in a pod. The fourth method means you have to write code to read the ConfigMap and its data. However, because you're using the Kubernetes API directly, your application can subscribe to get updates whenever the ConfigMap changes, and react when that happens.

A ConfigMap doesn't differentiate between single line property values and multi-line file-like values. What matters is how Pods and other objects consume those values. This is because the Pod definition specifies an items array in the volumes section.

If you omit the items array entirely, every key in the ConfigMap becomes a file with the same name as the key, and you get 4 files. ConfigMaps can be mounted as data volumes.