Tag: Docker

Dockerfile Best Practice

Build Modular Images i.e. Decouple applications

Create a seperate image for each application. Containers can talk to each other and can form a single large application and helps to scale each application

Don’t sotre data in Images

Images are read-only layer. When a container or image is deleted the data is lost

Use Cache Busting strategy

Install the repositories and packages together. As the docker file ises layered architecture having a seperate command for updating repositories and packages may not gurantee the repsoitories will be upto date and may result in dependency issue.

Use Version Pinning

When installing packages specifiy which version you want to install as everytime the image is build it will install the latest package where a application may not be compatible. Version pinning will always ensure the image will have specific version which your application supports.

Create slim images

This will help pull the images from which ever repository you are using quickly

Install only necessary or required packages

This will make image slim or with minimal packages and no unwanted packages are installed so every time image is build with minimal packages the build is fast and light weight. Also the containers created from such images are light weight and fast.

Maintain different images for different environements

Development images may contain debug tools and temprorary files required for debugging and bulding your application. However there tools are not required for production images. Hence remvoe any temporary files/folder and such tools for prodcution by creating a seperate image for different environments.

Use multi-stage builds to create images

Multi-stage build helps to or uses multiple FROM statements where each FROM instruction can use a different base, and each of them begins with new stage of the build and everything that is required for application is in the final image leaving behind unwanted files. This will avoid executing any script that was done traditionaly.

Exclude any unwanted files and folders using .dockerignore file

Use .dockerignore to exlcude any unwanted files and folders e.g.:- temp folder etc. this make the image lighter.

Use CMD instructions to run software in Image

Use CMD instructions to run the software contained in your image along with arguments. CMD should be used in JSON format that is the command and parameters should be seperated by comma.

Minimize build times

By avoiding to send unwanted files to the build context using .dockerengine

References –

https://docs.docker.com/develop/develop-images/multistage-build/

https://docs.docker.com/develop/develop-images/dockerfile_best-practices/

Use Docker Image offline with Save and Load command in Ubuntu

Docker Save and Load command

At times if you dont want to always pull the image from image registry which takes time to pull if the image’s are heavy, it makes sense to save the image and use it offline. This avoids to always pull the image from the registry.

Save the image once into tar file and reuse the images.

To Save image use follwoing command

First pull the image from repository

docker pull httpd
docker image save httpd -o httpdimage.tar

Get the image from the tar file instead pulling it from the registry

docker image load -i httpdimage.tar

Docker Restart Policies

To setup restart policy to the container, use following command-

docker run --restart=<<policy option>> <<container>>

Following are the options for the container restart-

  1. no (default)
  2. on-failure
  3. always
  4. unless-specified

Following is the matrix for the restart policies-

* – this will start when the Docker daemon is started

Above is applicable if the container starts successfully

Live Restore

If you want to keep container running if the Docker daemon crashes or stops use the live restore option. This reeduces the container downtime due to daemon crashes or planned outages or upgrades.

Update the /etc/docker/daemon.json in Ubuntu system and add option live-restore:true

Cache Busting and Version Pinning when building Docker images

docker file – Layered Architecture

Docker uses Layered Architecture. When using Docker files it creates a new layer in the image which adds additional space to the image based on the instructions for that layer.

When a Docker build command is run it proceeds from the first instruction in Docker file to the last while caching each stage so as if the build fails next time build uses cache until it ran succesully and invalidated the stage that failed and the following stage. Layers repurpose the previous layers and don’t have to build all of them again.

In below example Docker file has 6 stages. Each stage will be cached when build command is ran.

Suppose a build fails at Stage 3 due to some reason or new package has to be added the Docker will invalidate the Stage 3 and the following stages

Next time when a issue is rectified the build command will repurpose the previuos layers and build the failed stages

docker file – Layered Architecture

But in this case the repository will not be update, so how to resolve or update the repository with the packages-

Cache Busting

In this case we can to combine the instructions so the repository is updated along with packages as below

docker file – Cache Busting and Version Pinning

Merging Stage 2 and Stage 3 from the previous docker file in to single instruction will ensure the repository is first udpated and pakages are installed

Merging these stages is called as Cache Busting

Version Pinning

You can also explicity mention the version of package to be installed

In stage 2 docker file is instrcuting to install python3-pip 21.3.1 version

Best Practice-

Instructions which are most frequently modified should be at the bottom of the file and the instructions which are least modified should be at the top of the docker file

Docker storage for Ubuntu

Docker uses storage drivers to store the read-only images and writable containers

It basically has 6 layers

Read-only/Image Layers

  1. Base Image e.g. Ubuntu OS
  2. Packages/Repositories e.g. apt etc
  3. Dependencies e.g. pip etc
  4. Custom Code e.g. python code etc
  5. Enrtypoint or command i.e. excutes the program

Writable Layer

6. Container Layer

Layers of a container based on the Ubuntu image

Data and files related to images and containers are store in /var/lib/docker folder in Ubuntu

To check the storage driver used by the docker, use following command-

docker info | more

Im my case it is overlay2

You can also use this command to get the storage driver

docker info | grep "Storage Driver"

How to change the storage driver

Stop the Docker service

systemctl stop docker.socket
systemctl stop docker

Check the docker service status

service docker status

Backup the docker folder

cp -au /var/lib/dovker /var/lib/docker.bk

Change the storage driver

echo '{ "storage-driver": "aufs" }' | sudo tee /etc/docker/dameon.json
service docker start

Image credit and reference links –

https://docs.docker.com/storage/storagedriver/

https://docs.docker.com/storage/storagedriver/overlayfs-driver/

Step-by-step install Sitecore XP 10.1 to developer workstation using Sitecore Containers with Docker

To know more about containers here is the official documentation from Sitecore on Containers

Lets get started to create a Sitecore XP 10.1 development environment using docker.

Before getting started please see Installation Guide for Developer Workstation with Containers

Topology user here will XP0 or per guide XP Workstation (XP Single)

Hardware and Networking Requirements-

Sitecore instance needs below ports, avoid using these ports other than Sitecore.

Required portRoleDescription
443TraefikHTTPS proxy
8079TraefikTraefik dashboard
8984SolrSolr API and dashboard
14330SQLSQL Server

Prepare/prerequisite for Sitecore XP workstation

  • [Optional] OS- Windows 10 1809 or later or Windows Server 1809 or later

Login to Azure portal to create a VM

Image – Select Image to Windows 10 Pro, Version 1809- Gen 1

Size – Standard_D8s_v3- * vcpus, 32GiB memory

Inbound ports– Select RDP, dont select HTTPS 443 as this will be used by Traefik as mentioned in previous section

  • Download and Install Docker Desktop for Windows

Download and install Docker Desktop for Windows. You can get Stable version from here

After installation Restart the machine, this should enable the Hyper-V feature

This should also have Docker running and should see the same in system tray

  • Switch to Windows containers

Right click on Docker icon and switch to Windows Container. See this link for more details as per guide

Download and Prepare for installation

  • Download and extract the Sitecore Container Deployment Package from the Sitecore Developer Portal and store it on your local workstation or check releases here
  • Copy and extract SitecoreContainerDeployment.10.1.0.005207.309.zip for e.g:- C:/sc101_install

Navigate to C:\sc101_install\compose\ltsc2019\xp0

  • Open .env file, we need to fill in this parameters before starting installation. You can find more details in guide for each option.
  • Download PowerShell script to initialize (init.ps1) the parameters from docker-examples. Parameter values in .env can be populated manually by individually executing the commands for required for each parameter in guide(see Appendices) but I would recommend to use init.ps1 as this is provided by Sitecore and hence tried and tested.

Folder structure should look like this-

  • Change parameter values in init.ps1 file.

Change the SitecoreAdminPassword, SqlSaPassword and host entries as per requirement. If you are changing host entries also ensure the same is updated in .env file for CM_HOST and ID_HOST parameters. Lets keep the default values.

  • Populate .env file using init command

Open PowerShell as a Administrator, navigate to the folder having init.ps1 file.

Execute init.ps1 script. You may have to set the execution rights to current user to execute the script-

Set-ExecutionPolicy -Scope CurrentUser Unrestricted
.init.ps1

Provide the path of license file

This should Install and Import SitecoreDockerTools and Populate the environment file.

Ensure to Switch to Windows Container before executing below command

Install

Execute docker compose command

docker-compose.exe up --detach

Installation complete-

Once command execution is complete, should see all the checks done and Sitecore dev. instance ready in 20 minutes

Open Docker Dashboard and should see Sitecore-XP0 running

Site listening to address- https://xp0cm.localhost/

Cleanup the workstation

To cleanup/stop workstation use following commands. You can find these in instllation guide

To stop a Docker Compose environment without removing its contents:

docker-compose.exe stop

To resume a previously stopped Docker Compose environment:

docker-compose.exe start

To remove a Docker Compose environment and all the non-mounted volumes

docker-compose.exe down

Hope this helps to install Sitecore XP 10.1 using Docker!!!

Step-by-step install Sitecore XP 10 to developer workstation using Sitecore Containers with Docker Compose

One of the highlights of newly released Sitecore Experience Platform (10.0) is that it brings support to rapid deployment and more efficient solution and team onboarding with modern Docker technology i.e. Sitecore Containers.

To know more about containers here is the official documentation from Sitecore on Containers

Lets get started to create a Sitecore XP 10 development environment using docker.

Before getting started please see Installation Guide for Developer Workstation with Containers

Topology user here will XP0 or per guide XP Workstation (XP Single)

Hardware and Networking Requirements-

Developer workstation requires 32GB RAM and 25 GB Free space with quad core or higher CPU

Required portRoleDescription
433 443TraefikHTTPS proxy
8079TraefikTraefik dashboard
8080TraefikHTTP proxy
8984SolrSolr API and dashboard
14330SQLSQL Server

IMPORTANT-

HTTPS proxy port for Traefik in guide is incorrect. As per the docker-compose.yml the Traefik is set to listen on 443 port and not 433.

Prepare/prerequisite for Sitecore XP workstation-

  • OS- Windows 10 1809 or later or Windows Server 1809 or later

Login to Azure portal to create a VM

Image – Select Image to Windows 10 Pro, Version 1809- Gen 1

Size – Standard_D8s_v3- * vcpus, 32GiB memory

Inbound ports– Select RDP, dont select HTTPS 443 as this will be used by Traefik as mentioned in previous section

  • Download and Install Docker Desktop for Windows

Download and install Docker Desktop for Windows. You can get Stable version from here

Setup should enable Hyper-V Windows Features

After installation Restart the machine, this should enable the Hyper-V feature

This should also have Docker running and should see the same in system tray

  • Switch to Windows containers

Right click on Docker icon and switch to Windows Container. See this link for more details as per guide

Download and Prepare for installation

  • Download and extract the Sitecore Container Deployment Package from the Sitecore Developer Portal and store it on your local workstation

Login to Sitecore portal before download

  • Copy and extract SitecoreContainerDeployment 10.0.0 rev. 004346-027.zip for e.g:- C:/SitecoreXPDocker

Navigate to C:/SitecoreXPDocker/ltsc2019/sitecore-xp0

  • Open .env file, we need to fill in this parameters before starting installation. You can find more details in guide for each option.
  • Download PowerShell script to initialize (init.ps1) the parameters from docker-examples. Parameter values in .env can be populated manually by individually executing the commands for required for each parameter in guide(see Appendices) but I would recommend to use init.ps1 as this is provided by Sitecore and hence tried and tested.

Folder structure should look like this-

  • Change parameter values in init.ps1 file.

Change the SitecoreAdminPassword, SqlSaPassword and host entries as per requirement. If you are changing host entries also ensure the same is updated in .env file for CM_HOST and ID_HOST parameters. Lets keep the default values.

  • Populate .env file using init command

Open PowerShell as a Administrator, navigate to the folder having init.ps1 file.

Execute init.ps1 script. You may have to set the execution rights to current user to execute the script-

Set-ExecutionPolicy -Scope CurrentUser Unrestricted
.init.ps1

Provide the path of license file

This should Install and Import SitecoreDockerTools and Populate the environment file.

Ensure to Switch to Windows Container before executing below command

Install

Execute docker compose command

docker-compose.exe up --detach

Installation complete-

Once command execution is complete, should see all the checks done and Sitecore dev. instance ready in 20 minutes

Open Docker Dashboard and should see Sitecore-XP0 running

Site listening to address- https://xp0cm.localhost/

Cleanup the workstation

To cleanup/stop workstation use following commands. You can find these in instllation guide

To stop a Docker Compose environment without removing its contents:

docker-compose.exe stop

To resume a previously stopped Docker Compose environment:

docker-compose.exe start

To remove a Docker Compose environment and all the non-mounted volumes

docker-compose.exe down

Hope this helps to install Sitecore XP 10 using Docker!!!