A Technical I.T./DevOps Blog
Problem scenario
You want to bypass Docker and configure the cgroups directly. You want new Docker containers to be governed by these customized settings. What should you do?
Solution
You may not want to bypass Docker for your cgroup modifications. You should read about the libcontainers. By default Docker uses libcontainers for granular configuration changes along the lines of modifying cgroups settings.
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Problem scenario
You are using AKS (Azure Kubernetes Service). You have a cluster that you want to have more nodes. (Please do not confuse nodes with pods; see this posting if you are not sure about the difference.) What should you do?
Solution
You need to know the name of the cluster and the resource group it is in.
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Continue reading “How Do You Scale Out the Nodes of an AKS Cluster?”
Question
You have noticed that Docker and Jenkins are regularly used together. Why is this?
Answer
1. The docker build command produces one artifact. Jenkins lends itself to well-defined tasks.
2. The logic and dependencies of the build can usually be completely contained in the Dockerfile (page 20 of Docker Up and Running). Simple lines of text can standardize many aspects of a given build (e.g.,
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Problem scenario
You want to deploy the Spring framework with Docker. How do you do this?
Solution
Warning: The last step in this is not a security “recommended practice.” Only follow these directions (with sudo docker run…), if the server is not that important or you are in a very secure network. One published book says you can use “sudo docker …” as long as the server is not in production (page 43 of Docker Up and Running).
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Continue reading “How Do You Install Spring Framework with Docker?”
Question
What is a Secret in Kubernetes?
Answer
It is a ConfigMap with sensitive data that is encoded in Base64 text. What is a ConfigMap? It is a .yaml with a special format. There is always a “data:” section that is part of the YAML definition of a ConfigMap. The key-value pairs in the “data” section will have keys that appear in regular text;
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Problem scenario
You run this command: kubectl get svc
You receive this:
” could not get token: NoCredentialProviders: no valid providers in chain. Deprecated.
For verbose messaging see aws.Config.CredentialsChainVerboseErrors”
What should you do?
Solution
Install and configure the AWS CLI. If you need assistance with this, see this posting.
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Question
In Kubernetes you have heard of these things: service, deployment, HPA, pod, ingress, secret, configmap, and node. What are they?
Answer
Click on the relevant question for its answer:
What is a Secret in Kubernetes?
What is a ConfigMap in Kubernetes?
What is a Deployment in Kubernetes?
What is an Ingress Resource in Kubernetes?
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Problem scenario
You want to use Azure’s Kubernetes PaaS offering using the GUI. What do you do?
Solution
1. Sign into the Azure portal.
2. Click on “Services” on the left.
3. Click on “Containers”.
4. Click on “Kubernetes services”.
5. Click “Add”.
6. Fill out the required fields.
7. Click the “Review + create” button.
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Continue reading “How Do You Deploy AKS (Azure’s Kubernetes) Using the GUI?”
Question
What is a ConfigMap in Kubernetes?
Answer
A ConfigMap is a mapping of configuration originally in YAML format that resides in etcd (partially taken from this external posting). A .yaml file will define the version of the Kubernetes API (e.g., version 1), data, and the “kind:” key will be set to “ConfigMap”.
The content of the ConfigMap is consumed by an application in Kubernetes.
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Question
What is an HPA in Kubernetes?
Answer
HPA stands for HorizontalPodAutoscaler. It is a concept and resource that allows clusters to scale out upon a certain condition being met. HPA can support a pod to scale based on certain amounts of CPU utilization. It natively supports granular CPU requests down to a single millicore. A .yaml file in Kubernetes has the key “kind”;
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