How to install DRBD on Alpine Linux Latest

DRBD, or Distributed Replicated Block Device, is a Linux kernel driver that synchronizes blocks of data between multiple servers over a network. It ensures high availability and data consistency in case of server failure or maintenance. In this tutorial, we will explain how to install DRBD on Alpine Linux Latest using the official Linbit repository.

Prerequisites

To follow this tutorial, you will need:

A server running Alpine Linux Latest
Root access to the server
Working internet connection

Install Dependencies

DRBD requires a few dependencies to be installed before we can proceed with the installation. Here's how you can install them:

apk update
apk add linux-headers alpine-sdk curl gcc g++ make

Add Linbit Repository

DRBD is not available in the official Alpine Linux repository. Therefore, we need to add the Linbit repository to our system. You can do this by running the following command:

echo "http://download.opensuse.org/repositories/home:/linbit:/drbd-alpine-3.12:/testing/x86_64/" >> /etc/apk/repositories

Install DRBD Packages

Now that we have added the Linbit repository, we can proceed with the installation of DRBD packages. Run the following command to install DRBD:

apk update
apk add drbd drbd-utils

Configure DRBD

After the installation of DRBD, we need to configure it according to our requirements. The configuration file for DRBD is located at /etc/drbd.d/.

Create a new configuration file:

touch /etc/drbd.d/drbd.conf

Edit the configuration file as per your requirements. Here's an example configuration file:

resource r0 {
  # Define the two nodes that will share the DRBD device.
  # node1 is our local node, and node2 is the remote node
  on node1 {
    device    /dev/drbd0;
    disk      /dev/sda1;
    address   192.168.0.1:7788;
    meta-disk internal;
  }
  on node2 {
    device    /dev/drbd0;
    disk      /dev/sda1;
    address   192.168.0.2:7788;
    meta-disk internal;
  }

  # Set the synchronization method and protocol
  syncer { }
  protocol B;

  # Set up the disk synchronization
  disk {
    on-io-error   detach;
  }

  # Enable read-balancing
  net {
    protocol        C;
    after-sb-0pri   discard-zero-changes;
    after-sb-1pri   discard-secondary;
    after-sb-2pri   call-pri-lost-after-sb;
    max-buffers     8000;
    max-epoch-size  8000;
    sndbuf-size     0;
    rcvbuf-size     0;
  }

  # Choose auto-promotion policy
  on node1 {
    disk {
      no-disk-flushes;
      no-md-flushes;
    }
  }
  on node2 {
    disk {
      no-disk-flushes;
      no-md-flushes;
      no-disk-barrier;
    }
  }
}

Start DRBD Service

After the configuration is done, we can start the DRBD service. Run the following command to start the DRBD service:

rc-service drbd start

Verify DRBD Setup

To verify that DRBD is working correctly, we can run the following command:

cat /proc/drbd

This will display the status and configuration of the DRBD device.

Conclusion

In this tutorial, we have explained how to install and configure DRBD on Alpine Linux Latest. With DRBD, we can ensure high availability and data consistency in case of server failure or maintenance.