Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Analysis: kubectl describe svc kubernetes ‘kubernetes’ is a clusterIP service. (ie can be accessed only inside the cluster.) It has no selector specified.( So no automatic LB.) But endpoints specified(maybe hardcoded) as 172.31.15.134:6443 ( that means all the requests to this service will be routed to 172.31.15.134:6443) Now you can see the its the

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now It is an atomic scheduling unit in a Kubernetes cluster. It is a logical unit. Every container running in the cluster nodes will be wrapped up by the POD. In one POD there can be multiple container running. It is called tight coupling. Prefered way is run one container in one POD. It is

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now API Server: All the incoming/outgoing communication with Kubernetes cluster happening through API Server. APIServer is a RESTful server. Workstations/Client uses Kubectl tool for communicating with the API Server. API Server expects the inputs in JSON format. All the communication with the Master node worker nodes are also happening through API Server. Scheduler/Controller Manager uses

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Kubelet: Resides in each worker nodes. Registers the node to the master node. Instantiate the Pods. Container Runtime (Docker): For managing and running the containers. Kube-Proxy: It is a nw proxy. Implements nw rules on PODS. Fecilitate the communication with in the cluster and outside the cluster. All the networking related supports are done

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Kubernetes is an Orchestrator for running containers.Kubernetes provides auto scalability.Kubernetes provides load balancing.Kubernetes provides self healing feature.Kubernetes provides automated rollouts and rollbacks.Kubernetes has persistant storage.Kubernetes provides service discovery.Kubernetes has secrets and config management.Kubernetes provides automatic bin packing.Kubernetes design follows microservice architecture.

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now overlay2 overlay2 is the preferred storage driver for all currently supported Linux distributions, and requires no extra configuration. fuse-overlayfs fuse-overlayfsis preferred only for running Rootless Docker on a host that does not provide support for rootless overlay2. On Ubuntu and Debian 10, the fuse-overlayfs driver does not need to be used, and overlay2 works even in rootless mode. Refer to

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Docker image is a collection of files systems. It will have a ROOT FS, USR FS, APP FS. ONE Copy of Docker image get attached to each Container From one Image – you can get multiple Container. Docker uses storage drivers to store image layers, and to store data in the writable layer of

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Dockerfile commands DOCKER file Commands Details 1 FROM Taking the base image 2 MAINTAINER Creater of the dockerfile 3 RUN Run command in the container of the previous layer 4 ARG Set a variable for the dockerfile and reuse it ${var}. Scope is only during the building process. 5 EXPOSE Specifying information port for

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now https://devopsschool.com/tutorial/docker/dockerfile/dockerfile-example-sample-lab.html Docker File 1: /usr/sbin/apache2ctl specified in CMD will run in foreground as a blocking call. Docker File 2: Just exit after echoing “Hello world”. Docker File 3: Just exit after echoing “Hello”. Docker File 4: Same as ‘Docker File 1‘ except port 80 will be shown as exposed port. Docker File 5: Output

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Dockerfile with 2 CMD, 2 ENTRYPOINT: File content: Output: Welcome to /bin/sh -c echo “DOCKER” Observations: Both CMD and ENTRYPOINT entries will be overwritten with the latest entries. That is only the last CMD and ENTRYPOINT will be taken. Also the values specified in CMD will be add as an argument to the ENTRYPOINT

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Docker supports several storage drivers, using a pluggable architecture. The storage driver controls how images and containers are stored and managed on your Docker host. Docker uses storage drivers to store image layers Docker uses storage drivers to store data in the writable layer of a container. The container’s writable layer does not persist

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Tried: docker pull dockerdocker pull fluentddocker pull pypydocker pull centosdocker pull mongo

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Block until one or more containers stop, then print their exit codes. Example: Terminal 1: root@ip-172-31-28-155:/home/ubuntu# docker wait test_su1 Terminal 2: root@ip-172-31-28-155:/home/ubuntu# docker stop test_su1 Terminal 1: root@ip-172-31-28-155:/home/ubuntu# docker wait test_su10

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Used for updating the various confgurations of a container or multiple containers. We can update the configuration of running/stopped containers except –kernel-memory. Various Options available. Use case: The main usecase is to limit the amount of host resources like CPU, RAM , that can be used by the container.

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Docker Puase: Just puasing all processes inside the container by generating a SIGSTOP signal. Process state will goes to suspended. Docker Unpuase: Resuming the container porcesses.

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Docker stop: Graceful exit. Apps can catch the signal(SIGTERM) and ignore/handle it. Normally APPS will do some cleanup activities by handling it. Docker Kill: Forceful exit. Generate SIGKILL signal.Apps can’t catch or ignore.

Limited Time Offer! For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly. Master DevOps, SRE, DevSecOps Skills! Enroll Now Docker Container: A running instance of docker container image. Docker Container Image: It is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings. Its basically a collection of file systems. It will have a ROOT FS, USER FS and one