Configuring Lightbits Target Virtual Machines
This article details how to prepare the Lightbits storage VMs for running the Ansible installer packages and creating a cluster.
SSH into your Lightbits target VM using a method described in the SSH Into An Azure VM section.
Installing wget
To pull packages, we will use wget. If you have another preferred tool, you can use your organization's best practices instead.
sudo yum install -y wgetInstalling the Correct Kernel
Lightbits software involves installing Lightbits proprietary kernel modules on the VMs in the storage cluster. As a result, a specific kernel must be used. The mapping of kernels to Lightbits versions is outlined below.
As noted in the table, releases 3.4.1 and above live in user space. This step can therefore be skipped since the kernel is no longer relevant. Please move on to the Disabling SELinux section.
| Lightbits Release | Release Type | Kernel Version | Supported OS |
|---|---|---|---|
| 3.7.1~b1548 | RHEL | User space | Alma, RHEL, Rocky (8 & 9) |
| 3.6.1~b1503 | RHEL | User space | Alma, RHEL, Rocky (8 & 9) |
| 3.5.1~b1443 | RHEL | User space | Alma, RHEL, Rocky (8 & 9) |
| 3.4.1~b1397 | RHEL | User space | Alma, RHEL, Rocky (8 & 9) |
| 3.3.1~b1335 | RHEL | 4.18.0_477.13.1.el8 | Alma, Red Hat 8.7 |
| 3.2.1~b1252 | RHEL | 4.18.0-425.19.2.el8 | Alma, Red Hat 8.6 |
| 3.1.2~b1127 | RHEL | 4.18.0_425.3.1.el8 | Alma, Red Hat 8.6 |
| 3.1.1~b1119 | RHEL | 4.18.0-425.3.1.el8 | Alma, Red Hat 8.6 |
In this guide, the examples illustrate using Lightbits release 3.2.1.
Azure does not allow for fully configuring RHEL kernel versions, so we will illustrate how to use Alma open source kernels. If your organization has access to the RHEL kernels, follow your organization's internal best practices.
- Download the kernel packages from the Alma repository, using wget.
wget https://repo.almalinux.org/almalinux/8.7/BaseOS/x86_64/os/Packages/kernel-core-4.18.0-425.19.2.el8_7.x86_64.rpmwget https://repo.almalinux.org/almalinux/8.7/BaseOS/x86_64/os/Packages/kernel-modules-4.18.0-425.19.2.el8_7.x86_64.rpmwget https://repo.almalinux.org/almalinux/8.7/BaseOS/x86_64/os/Packages/kernel-4.18.0-425.19.2.el8_7.x86_64.rpm- Install the kernel packages.
sudo rpm -i "kernel-core-4.18.0-425.19.2.el8_7.x86_64.rpm"sudo rpm -i "kernel-modules-4.18.0-425.19.2.el8_7.x86_64.rpm"sudo rpm -i "kernel-4.18.0-425.19.2.el8_7.x86_64.rpm"- Set the kernel in grubby.
sudo grubby --set-default="/boot/vmlinuz-4.18.0-425.19.2.el8_7.x86_64"- Prevent the yum update from changing the kernel version.
echo 'exclude=redhat-release* kernel* kmod-kvdo*' | sudo tee -a /etc/yum.confInstalling IP Tables
For Lightbits, we use iptables by default.
- Install iptables.
sudo yum install -y iptablesDisabling SELinux
For the Lightbits installation to succeed, SELinux must be disabled.
- Disable SELinux.
sudo sed -i 's/^SELINUX=.*$/SELINUX=disabled/' /etc/selinux/configEnabling Persistent Journaling
To aid with troubleshooting and support, Lightbits recommends setting the journal to keep logs even after reboots and shutdowns. To ensure that the OS disk does not fill up, Lightbits also recommends updating the log rotation.
- Enable persistent journaling.
sudo sed -i 's/#Storage.*/Storage=persistent/' /etc/systemd/journald.conf- Enable log rotation.
sudo sed -i 's| missingok$| daily\n rotate 30\n compress\n missingok\n notifempty|g' /etc/logrotate.d/syslogRebooting as Needed
To ensure that the kernel changes have been applied, reboot the virtual machine.
sudo shutdown -r nowRepeating the Process as Needed
Repeat the above process for all virtual machines that will be a part of the Lightbits storage cluster.