Docker Supervisor

-


Traditionally a Docker container runs a single process when it is launched, for example an Apache daemon or a SSH server daemon.

Often though you want to run more than one process in a container. 

There are a number of ways you can achieve this ranging from using a simple Bash script as the value of your container’s CMD instruction to installing a process management tool.

Supervisor, to manage multiple processes in a container.

Using Supervisor allows you to better control, manage, and restart the processes inside the container.

Lets say you want to create SSH process running on the docker container.

Lets build the image file.

1) Will use ubuntu image.

2) Install SSH and Supervisord.

3) Create folder for SSH and supervisor.

4) Create supervisord.conf and update with SSH startup command.

5) Copy the supervisord.conf to the image.

6) Expose port # 22.

7) Start the supervisord.

root@masterk8s:/docker# cat supervisord.conf

[supervisord]

nodaemon=true

[program:sshd]

command=/usr/sbin/sshd -D

root@masterk8s:/docker#

Now, Lets start creating the docker image file.

root@masterk8s:/docker# cat dockerfile

FROM ubuntu:latest

RUN apt-get update

RUN apt-get install openssh-server -y

RUN mkdir /var/run/sshd

COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf

root@masterk8s:/docker#

root@masterk8s:/docker# docker build -t rajasekar:supervisord .

Due to DNS issue inside the docker. I am spawing the docker container with network - host or we can build using host network.

root@masterk8s:/docker# docker build --network=host -t rajasekar:supervisord .

root@masterk8s:/# docker images  | grep -i supervisord

rajasekar                          supervisord   c0c3d44967d0   35 seconds ago   227MB

root@masterk8s:/#

root@masterk8s:/# docker history c0c3d44967d0

IMAGE          CREATED          CREATED BY                                      SIZE      COMMENT

c0c3d44967d0   50 seconds ago   /bin/sh -c #(nop)  CMD ["/usr/bin/supervisor…   0B

52f96147e7ac   50 seconds ago   /bin/sh -c #(nop)  EXPOSE 22                    0B

2dad551e9d21   51 seconds ago   /bin/sh -c #(nop) COPY file:7381c7204f81628f…   70B

5b45d5ba8ddf   51 seconds ago   /bin/sh -c mkdir /var/run/sshd                  0B

27ab7d5be6ad   53 seconds ago   /bin/sh -c apt-get install openssh-server -y    110MB

ce70a0d553e1   5 minutes ago    /bin/sh -c apt-get update                       39.6MB

a8780b506fa4   13 days ago      /bin/sh -c #(nop)  CMD ["bash"]                 0B

<missing>      13 days ago      /bin/sh -c #(nop) ADD file:29c72d5be8c977aca…   77.8MB

root@masterk8s:/#

Image is completed. Lets create a container.

root@masterk8s:/docker# docker run -it -p 8080:22 c0c3d44967d0 bash

root@5a004a6876ce:/#

root@masterk8s:~# docker container ls

CONTAINER ID   IMAGE          COMMAND   CREATED          STATUS          PORTS                                   NAMES

5a004a6876ce   c0c3d44967d0   "bash"    30 seconds ago   Up 24 seconds   0.0.0.0:8080->22/tcp, :::8080->22/tcp   nifty_chaplygin

root@masterk8s:~#


Comments

Post a Comment

Popular posts from this blog

SRE/DevOps Syllabus

-
Image
  DEVOPS/SRE Principles. Git What is Git? Architecture of Git. Working principle of Git. Create and cloning a repo. Version control branching. Version control commit. Version control managing workflows. Git hooks. Git Reflog. Git Stash. Git Cherry Picking. Undoing changes in different states of Git. Git based terraform template management. AWS CI/CD SDLC Automation. Code Commit. Code Build. Code Deployment. Code Pipeline. Elastic Beankstalk. Code Artifact. CodeGuru. Terraform Terraform Basics. Terraform State. Working with Terraform. Terraform with AWS. Remote State. Terraform Provisioners. Terraform Import, Tainting and Debugging. Terraform Modules. Terraform Functions and Conditional Expressions. Automation using Python - AWS AWS lambda. Automating EC2 with Lambda. Automating S3 with Lambda. Automating VPC with Lambda. Cost optimization with Lambda. SNS,SQS and SES with Python. Managing and Automating AWS Security with Python. Kubernetes - CKAD Application Developer. Kubernetes A...
Read more

AWS Code Commit - CI/CD Series Part 1

-
Image
  This is a multi-part series to show how to implement a CI/CD pipeline in AWS. In this post, We will see how to use AWS Code Commit. AWS CodeCommit is a fully managed source control service that allows you to store and manage your code securely in the cloud.  It provides a private Git repository for your code and supports all Git commands and workflows. CodeCommit also integrates with other AWS services like AWS CodePipeline and AWS CodeBuild, allowing you to automate your entire software release process. This can help you streamline your development workflows and improve the overall efficiency of your team. I created a repo from AWS CodeCommit -> Create Repository. And I begin with cloning the repo locally. So that I can make changes and push it. To clone the repo click on "HTTPS" under Clone URL. I make changes to index.html file. Now push it to AWS CodeCommit. Let’s verify the changes in AWS Code commit. Changes are reflected in AWS CodeCommit. We are done with Part ...
Read more

Docker - Preventing IP overlapping

-
Image
  What is IP address overlapping? When the container IP address overlaps with another IP external, then the application running on the container is not accessible from outside due to the IP address overlapping.  NOTE: This IP address overlapping can happen on the bridge interface IP or docker container IP. Let's see how to address this IP overlapping issue on the bridge interface. I already have a running container.  root@demo:~# docker run -d --name web --network mynet1 nginx:alpine 268647e11011d513d2357ce1c81e0f48787038a83d01d028d31a5b29dbdb885b root@demo:~# docker container ls CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS     NAMES 268647e11011   nginx:alpine   "/docker-entrypoint.…"   4 seconds ago   Up 3 seconds   80/tcp  ...
Read more