EXPRESSCLUSTER 5 on Debian 12

Versions:

• EXPRESSCLUSTER X 5.3 for Linux
• Debian 12.11 (kernel 6.1.0-37-amd64)
• MariaDB 10.11.11 (an application to be protected)

Configuration:

• 2 nodes
• Data mirroring

---

Now in 2025.Jul.10, Debian 12.11 has an issue that cannot load the watchdog. Due to it, ECX userw cannot utilize softdog untill the forthcoming update of Debian.

https://www.debian.org/News/2025/20250517

Known Issues

Linux 6.1.137-1, included with Debian 12.11, is unable to load the watchdog and w83977f_wdt modules on the amd64 architecture. This is a regression.

This issue will be fixed in a forthcoming update.

Users who rely on the watchdog functionality should disable their watchdog or avoid upgrading to this kernel version until a fix is available.

A possible measure for now is omitting userw from the cluster configuration and rebert it once the problem on Debian will be fixed and the installation and configuration steps are as followings. The disadvantage of omitting userw is that the OS will not automatically reset if a long delay occurs. In a real system, operations would likely include manual operations such as "delay detection > manual stop > automatic failover". As for an automation measure, the utilization of forced stop resource is also described.

---

Installation and configuration steps

1. Servers preparation

   Prepare 2 servers. Each server has

   • 2 NICs
   • 2 DISKs

2. Debian installation and configuration

   Install Debian on /dev/sda.

   Configure disk /dev/sdb1 to be replicated by DRBD.

   Configure network:

   • eth0 to have 10.0.0.11/24 for public network example.
   • eth1 to have 192.168.0.11/24 for private network example.

3. ECX installation and configuraiton

   On both VMs, prepare the package and license files of EXPRESSCLUSTER in the current directory and run the followings.

   sudo apt install ./expresscls-5.3.0-1.amd64.deb
   sudo clplcnsc -i *
   sudo reboot

   On EXPRESSCLUSTER WebUI, make and apply the configuration of the cluster as following (to prepare the installation of DRBD and MariaDB in later section).

   • failover1
     • fip1
   • fipw
   • userw

   Remove userw monitor from the configuration.

   

   Refere to the Reference Guide about the Forced Stop resource. It helps to have a counter measure for processing delays in the absence of userw.

4. DRBD installation and configuration

   Follow the article explaining how to enable DRBD on Ubuntu 23, and the same instructions apply to Debian 11.

5. MariaDB installation & configuration

   Install MariaDB on both VMs.

   sudo apt update
   sudo apt install -y mariadb-server mariadb-client

   Follow the article explaining how to enable MariaDB on RHEL 9.0, and the same instructions apply to Debian 11. In the article, the parameter Libraly Path would be /usr/lib/x86_64-linux-gnu/libmariadb.so.3.

6. Confirm the cluster configuration

   It would be like this:

   • failover1
     • fip1
     • exec-DRBD
     • exec-MariaDB
   • fipw
   • genw-DRBD
   • diskw-DRBD
   • mysqlw-MariaDB

DRBD trouble shooting

Technical support for DRBD is often requested, even though it is a part of Linux. If your customer wants to have tech support for DRBD, they should first purchase tech Support for Linux from a Linux distributor, then buy the Tech Support for DRBD by Linbit.

DRBD Troubleshooting explains general methods for TS.