Linux Containers

1. What are LXCs?
Linux Containers (LXCs) are operating-system-level virtualization tools that allow multiple isolated Linux systems (containers) to run on a single host. LXCs provide an environment as close as possible to a standard Linux installation but without the need for a hypervisor, offering more efficient resource usage.

2. Use Cases for LXCs:

• Development and Testing: Developers can create isolated environments for testing and development.
• Microservices: Running different components of a microservice architecture in separate containers.
• Resource Efficiency: Sharing the same OS kernel reduces overhead compared to full virtual machines.
• Security: Isolation helps in reducing the attack surface by separating different applications.

3. Why Not Just Use Docker?
While both LXCs and Docker provide containerization, they have different focuses and use cases:

• LXCs:
• Provide a more complete virtualization environment, suitable for running full Linux distributions.
• Offer more control over the container environment, which can be beneficial for certain complex applications.
• Docker:
• Focuses on application-level isolation, packaging applications with their dependencies.
• Easier to use and integrate with modern CI/CD pipelines.
• Has a vast ecosystem with Docker Hub for container images.

Setting Up an LXC with MariaDB

Step 1: Install LXC

1. Update your package list and install LXC:

   sudo apt update
   sudo apt install lxc

2. Verify the installation:

   lxc-checkconfig

Step 2: Create and Configure a Container

1. Create a new LXC container:

   sudo lxc-create -t download -n mycontainer -- --dist ubuntu --release focal --arch amd64

This command creates a container named mycontainer using Ubuntu 20.04 (Focal Fossa).

2. Start the container:

   sudo lxc-start -n mycontainer

3. Attach to the container:

   sudo lxc-attach -n mycontainer

Step 3: Install MariaDB inside the Container

1. Update the package list inside the container:

   apt update

2. Install MariaDB server:

   apt install mariadb-server

3. Secure the MariaDB installation:

   mysql_secure_installation

4. Start MariaDB service:

   service mysql start

5. Verify MariaDB installation:

   mysql -u root -p

Step 4: Configure Network and Access

1. Exit the container:

   exit

2. Check the container’s IP address:

   sudo lxc-info -n mycontainer | grep IP

3. Adjust your host firewall and LXC configurations to allow access to MariaDB if needed.

Step 5: Manage the LXC Container

• Stop the container:

  sudo lxc-stop -n mycontainer

• Restart the container:

  sudo lxc-start -n mycontainer

• Destroy the container:

  sudo lxc-destroy -n mycontainer

Summary

LXCs provide a lightweight alternative to virtual machines and Docker containers, suitable for use cases requiring full Linux environments. They offer resource efficiency and security through isolation. By following the steps above, you can set up an LXC container running MariaDB, demonstrating the flexibility and power of LXC.