To understand images and their layers, you can always inspect the image history. Let’s inspect the history of the last Docker image by running the following command: As you can see, there are several layers, and every layer has associated commands. You can also see when the layers were created and the size of the […]
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Layers in Docker are intermediate Docker images. The idea is that every Dockerfile statement we execute on top of a layer changes something within the layer and builds a new one. The subsequent statement modifies the current one to generate the next one. The final layer executes the Docker CMD or ENTRYPOINT command, and the […]
Read More… from The layered filesystem – Creating and Managing Container Images
In the previous chapter, we covered containerization with Docker, where we installed Docker and ran our first container. We covered some core fundamentals, including Docker volumes, mounts, storage drivers, and logging drivers. We also covered Docker Compose as a declarative method of managing containers. Now, we will discuss the core building blocks of containers: container […]
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Use an .env file to store sensitive variables You might not want to store sensitive content such as passwords and secrets in version control. Instead, you can use an .env file that contains a list of variable names and values and keep it in a secret management system such as HashiCorp Vault. Be mindful of […]
Read More… from Be mindful of dependencies in production – Containerization with Docker
Docker Compose best practices Docker Compose provides a declarative way of managing Docker container configuration. This enables GitOps for your Docker workloads. While Docker Compose is primarily used in development environments, you can use it in production very effectively, especially when Docker runs in production and does not use another container orchestrator such as Kubernetes. […]
Read More… from Separate multiple environment YAMLs using overrides – Containerization with Docker
The next step in the process is to create a docker-compose file. A docker-compose file is a YAML file that contains a list of services, networks, volumes, and other associated configurations. Let’s look at the following example docker-compose.yaml file to understand it better: version: “2.4” services: flask: image: “bharamicrosystems/python-flask-redis:latest” ports: networks: redis: image: “redis:alpine” networks: […]
Read More… from Creating the docker-compose file – Containerization with Docker
Docker Compose helps you manage multiple containers in a declarative way. You can create a YAML file and specify what you want to build, what containers you want to run, and how the containers interact with each other. You can define mounts, networks, port mapping, and many different configurations in the YAML file. After that, […]
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From a conceptual point of view, there is no difference between container monitoring and the traditional method. You still need metrics, logs, health checks, and service discovery. These aren’t things that are unknown or haven’t been explored before. The problem with containers is the abstraction that they bring with them; let’s look at some of […]
Read More… from Challenges with container monitoring – Containerization with Docker
Docker allows you to run multiple applications in a single machine or a cluster of machines. Most organizations run a mix of virtual machines and containers, and they have their logging and monitoring stack configured to support virtual machines. Most teams struggle to make Docker logging behave the way virtual machine logging works. So, most […]
Let’s start by finding the current logging driver: $ docker info | grep “Logging Driver” Logging Driver: json-file Currently, the default logging driver is set to json-file. If we want to use journald or Splunk as the default logging driver, we must configure the default logging driver in the daemon.json file. Edit the /etc/docker/daemon.json file […]
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