Tips and best practices for Docker | Calidad Infotech

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Tips and best practices for Docker

• Numerous packaging delivering applications are
  available in the global market, and out of all,
  Docker has created its prominent reputation
  amongst countless organizations around the globe,
  especially for cloud-based applications.
• Docker is a widely used platform to develop run
  apps quickly by allowing users to keep them
  separate from the infrastructure. Dockers
  testing deploying methodologies help to
  mitigate the delays between writing codes
  running them.
• Docker provides phenomenal benefits such as the
  cluster of containers, scalability, rapid
  deployment with any dependencies. In this blog,
  we will walk you through the best practices of
  Docker in detail that will help you maximize the
  benefits of Docker by implementing them.

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Docker Best Practices for Image Building

• Version Images
• Docker users employ the latest tags for images,
  which are also the default tag. Using these tags
  will eliminate the possibility of identifying the
  running version code based on the image tag.
• It makes it straightforward to overwrite it.
  However, it leads to severe complications while
  doing rollbacks. Please avoid using the latest
  tag, especially for primary images, as it could
  lead to deploying a new code version.
• The best practice is using descriptors such as
  timestamps, semantic versions, or Docker Image
  IDs as tags. You can easily tie the tag to the
  code with the relevant tagging.

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Docker Best Practices for Image Building

• Version Images
• Docker users employ the latest tags for images,
  which are also the default tag. Using these tags
  will eliminate the possibility of identifying the
  running version code based on the image tag.
• It makes it straightforward to overwrite it.
  However, it leads to severe complications while
  doing rollbacks. Please avoid using the latest
  tag, especially for primary images, as it could
  lead to deploying a new code version.
• The best practice is using descriptors such as
  timestamps, semantic versions, or Docker Image
  IDs as tags. You can easily tie the tag to the
  code with the relevant tagging.

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• Imaging Linting
• Inspection of the source for any programmatic
  error that can cause issues is called Linting,
  which helps to ensure that the Dockerfiles comply
  with the correct practices. You can follow this
  process in images to determine any root-level
  vulnerabilities.

• Signing Validating Images
• There are scenarios when tampering with the
  images can occur due to human errors while
  running the production code. Using Docker Content
  Trust, you can sign validate the images to
  determine whether they have been tampered with.
  You need to set up the DOCKER_CONTENT_TRUST1
  environment variable.

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• Using .dockerignore File
• .dockerignore file helps to define the required
  build context. The user needs to specify the
  files folders before image building that should
  be excluded from the initial build context, which
  is sent to the Docker Daemon with the help of the
  .dockerignore file. The entire projects root is
  sent to the Docker Daemon before evaluating the
  COPY or ADD command.
• If the Docker Daemon and Docker CLI are on
  different machines, then the .dockerignore file
  should be added to the local development file,
  build logs, or temporary files. It will boost the
  build process, minimize the risk of secret leaks,
  and reduce Docker image size.

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• Avoid secrets storage in Images
• Confidential data and secrets, such as passwords,
  TLS certificates, SSH keys, and other highly
  sensitive information, must be avoided storing in
  images without encryption as it can lead to easy
  extraction and exploitation of confidential
  information. These situations can occur when
  images are pushed into a public registry.
• The best practice is injecting confidential
  information through environment variables,
  orchestration tools, and build-time arguments.
  You can also store sensitive information in the
  .dockerignore file. Also, ensure being specific
  about the files that must be copied over the
  image.

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• Environment Variables are primarily employed to
  keep the application secured flexible. It can
  also be used to pass on highly sensitive
  information and secrets. However, this
  information will still be visible in linked
  containers, docker inspect, logs, and child
  processes. We recommend encrypting the secrets if
  they need to be shared in a shared volume.

Dockerfiles Best Practices

• Multi-Stage Builds
• You can divide Dockerfiles into numerous stages
  via Multi-Stage Builds. With this break-up, you
  can easily discard the tools dependencies of
  application building in the final stage. In
  addition, Multi-Stage Builds lead to lean,
  modular, low-size, and secure images, thereby
  helping you save time cost.

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• Reducing Layers Number
• The image size increases with every layer due to
  caching. The best practice is to keep the image
  size minimal. You can reduce the number of layers
  by combining related commands wherever feasible.
• Apart from this, you can eliminate unwanted files
  in the RUN setup. Also, you can minimize the run
  apt-get update to achieve this task. However,
  reduce the number of layers whenever possible and
  not forcefully, as it can lead to irrelevant
  issues.

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• Small Docker Base Images
• The best practice for building, pushing, and
  pulling images is to ensure their size is as
  small as possible, which will fasten up the
  process and keep it safer. Also, ensure that only
  the essential dependencies libraries are
  included to run the application.

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• Using a single container for one process
• Running only one process per container is always
  advisable, even though an app stack can run
  multiple functions in a single container. It is
  one of the best practices for Dockerfiles as it
  makes the following services straightforward
• Scalability
• You can manage traffic by horizontally scaling
  the services with a single container.
• Portability
• With a single container, there are fewer
  processes to work on, making security patches
  plain sailing.
• Reusability
• You can employ the same database container when
  another service requires a containerized
  database.

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• Dockerfile Command Order
• Dockerfile commands play a pivotal role in its
  efficiency. Docker caches every layer in a
  specific Dockerfile to improve the builds. During
  any change in a step, the entire cache will
  become null for further steps, which is a highly
  inefficient practice in a Docker container.
• Instead of randomly putting files, the correct
  practice is to place frequently updated files at
  the end of the Dockerfile. You can also put
  layers with a higher possibility of lower changes
  in the Dockerfile and turn off cache in a Docker
  build wherever necessary by adding a
  no-cacheTrue flag.

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• Using COPY instead of ADD
• Many users perceive that both COPY ADD commands
  have the same purpose and nature as they are used
  to copy files from one location to a Docker
  image. However, there are differences between
  both. COPY helps to copy local files from the
  Docker host to the image.
• ADD also does the same, but it can also download
  external files unpacking the contents of any
  compressed file in a desired location. The
  primary preferred command should be COPY over
  ADD. However, you can use ADD if you want the
  additional functionality of the ADD command.

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Best Practices of Docker Development

• CI/CD for Testing Deployment
• When a pull request is created, Docker experts
  recommend employing Docker Hub or any other CI/CD
  pipeline to develop tag a Docker image. Also,
  the images must be signed by development,
  testing, and security teams before pushing them
  to production to ensure they are constantly
  tested for top-notch quality.

• Updating Docker
• Always update Docker to the latest version before
  starting to work on a Docker project, as you will
  have the latest features and updates. You can
  utilize security features and others to protect
  your project from attacks and threats.

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• Different Environments
• One of the best practices of Docker Development
  is to create different environments for
  development testing. It helps developers to
  keep Dockerfiles isolated run them without
  affecting the final build post-testing.

Best Practices for Docker Security

• APIs Network Configuration
• One of the biggest security threats for Docker is
  inappropriately configured API, which hackers can
  target. Ensure to configure API securely with
  practices like certificate-based authentication
  to keep containers secured from being exposed
  publicly.

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• Limit Container Capabilities
• Docker comes with a default configuration where
  users will see the capabilities that wouldnt be
  required to perform certain services. These
  unnecessary capabilities and benefits can be a
  doorway to hackers.
• The best practice to avoid these security
  breaches is to limit container capabilities by
  employing only those which are required by Docker
  containers to run apps.

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• Restrict System Resource Usage
• Each Docker container can use different
  infrastructure resources, such as CPU, network
  bandwidth, and memory.
• Limiting the system resource usage for each
  container ensures that no container employs
  excessive infrastructure resources than required.
  It will promote efficient use of resources, and
  no services will be disrupted.

• Using Trusted Images
• Using images from any source will adversely
  impact Dockers security. Hence, ensure to use
  Docker images only from trusted sources and
  configure them correctly. Also, make sure to get
  them signed by the Docker Content Trust.

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• Limit Access to Container Files
• Transitory container files are accessed more
  frequently, and they need constant bug fixes
  upgrades to secure them from getting exposed.
• You can solve this issue by maintaining container
  logs outside containers. It will limit the access
  to container files and keep them secured from
  getting accessed frequently.

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Best Practices of Docker Container

• Cloud Deployment
• While deploying a Docker container to a cloud, we
  recommend deploying the Kubernetes cluster. We
  recommend creating a standard virtual machine by
  the admins to deploy a single Docker container.
  The next step is securing the socket shell and
  installing Docker. After installation, admins can
  deploy applications on the cloud.

• Single Manager Node
• One of the most common Docker container practices
  is backing up a single manager node frequently,
  helping admins in restoration. Docker Swarm
  Universal Control Plane are part of every node.
  Hence, backing up a single manager node gets the
  job done for the admins.

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• Load Balancer
• Load Balancer helps admins get firm control over
  Docker containers, and they can foster containers
  to become highly scalable and available.
• A Load Balancer supports numerous balancing
  methods specific applications, rate limiting,
  and static dynamic caching. If you want to
  install a Load Balancer on Docker, contact us,
  and our proficient highly professional Docker
  experts will assist you with it.

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Best Practices for Docker Logging

• Dedicated Logging Container
• We recommend having a dedicated container for
  logging to eliminate dependencies on host
  machines, which will be accountable for log file
  management within the Docker environment.
• A Dedicated Logging Container will cumulate logs
  from other containers. It will automatically
  monitor analyze them. Also, it will forward the
  log files to a desired location. You can deploy
  more containers whenever needed with this Docker
  Logging practice.

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• Application Logging
• This practice involves directly logging from the
  application, and applications within the
  container manage to log via the framework. The
  developers will have firm control over the
  logging. Applications remain independent from
  containers with this practice.

• Sidecar Method
• Sidecar Method is one of the best practices for
  managing microservices architecture, as it runs
  the sidecars simultaneously with the parent
  application, sharing the same network volume.
  Shared resources allow expanding the app
  functionalities eliminate the installation need
  for extra configurations.

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• Drivers Logging
• Logging Drivers help read data by the stdout or
  stderr streams of the Docker container, as they
  are specifically configured to achieve this task.
  After this, the host machine stores log files,
  including preliminary data.
• Logging drivers help to centralize log files to a
  single desired location and are primarily used
  because being native to Docker.

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Best Practices for Docker Compose

• Running Compose on a Single Server
• You can employ compose for deploying an app to a
  remote Docker after setting up DOCKER_HOST,
  DOCKER_TLS_VERIFY, and DOCKER_CERT_PATH
  Environment Variables.
• After these variables are set up, the Docker
  compose commands will perform as desired without
  requiring additional configuration.

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• Adjusting Compose File for Production
• Making specific changes such as enhancing
  additional services, different setups for
  Environment Variables, binding multiple ports on
  the host machine, and eliminating volume bindings
  are critical for production.
• The best practice for achieving this task is
  defining a new compose file for specifying the
  desired configuration and only adding the
  required changes you want from the original
  compose file.
• For a new configuration, you can apply a new
  compose file over docker-compose.yml and direct
  compose to use the 2nd configuration file with
  the -f option.

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Conclusion

• After reading the blog, you will have a firm
  comprehension of the Best Practices of Docker
  Image Building, Dockerfiles, Docker Development,
  Docker Security, Docker Container, Docker
  Logging, and Docker Compose.
• By implementing these practices or even half of
  the mentioned practices in the blog, you will
  experience excellent results and enjoy
  significant benefits. However, if you have any
  questions or need more tips, feel free to contact
  us.
• At Calidad Infotech, we utilize Docker tools as
  part of our DevOps services, and our Docker
  experts have assisted numerous organizations in
  availing significant advantages of Docker in the
  short and long run.
• For a quotation of our Docker Tools, DevOps
  services, or application testing services,
  contact us at 91-9909922871 or email at
  hello_at_calidadinfotech.com.

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