A cluster is a group of modes where virtual machines run. Cluster nodes are physical servers. Before you add them into the cluster, you need to perform some configuration.
This article describes the requirements that must be met by the servers you want to use as cluster nodes.
Supported operating systems:
- CentOS 7 x64 (recommended)
You should install a minimal version of the operating system.
We don't recommend that you update the operating system of cluster node with major version changing.
Be sure to install the operating system of the same version on all cluster nodes. The control panel won't allow adding a cluster node if its operating system differs from the one installed on VMmanager server. For example, you cannot add a cluster node with CentOS 7.6, if the master server runs on CentOS 7.5.
If you are going to use the server in an OVH data center, enable the Install original kernel option when installing the OS via the OVH control panel.
- All cluster nodes must be in the same network;
- SSH must listen on the port 22 on every node;
- you can allocate 100-150 Gb for the root partition;
- disable protection from multicast storm;
- Pay attention to network capacity if you use network storages.
Allow incoming connections for the following ports:
- 22/tcp - SSH service, from all cluster nodes, and from the public network if needed
- 111/tcp - rpcbind for NFS, from all cluster nodes
- 662/tcp,udp - pftp for NFS, from all cluster nodes
- 892/tcp,udp - NFS, from all cluster nodes
- 1500/tcp - ihttpd, to access to the control panel web-interface from the public network and access the panel services on a cluster node
- 1515/tcp - vmwatch-master monitoring of a VM state, from all cluster nodes on the server with the control panel
- 2049/tcp,udp - NFS, from all cluster nodes
- 32803/tcp - NFS, from all cluster nodes
- 32769/udp - NFS, from all cluster nodes
- 5900-6900/tcp - QEMU VNC. If access to VNC can be performed only via the control panel, the range of ports must be allowed for the network combining cluster nodes
- 15900-16900/tcp - websockify, QEMU VNC translation for the noVNC web-interface, access from the public network
- 49152-49261/tcp - libvirt migration services.
Recommended configuration of the disk subsystem
When installing an operating system on cluster nodes we recommend using XFS as the file system.
OS templates that VMmanager uses for guest OS are about 80 GB (the largest templates are WIndows - 10-15 GB each template. Every Unix template requires about 100 MB). Templates are located in the /nfsshare/ directory, which is duplicated to each cluster node. Allocate 60-80 Gb of disk space to /nfsshare. If you are planning to install Windows on guest systems or create custom OS templates, you may allocate less space to the partition.
If you plan to make backup copies, make sure you have in the root section has additional free space: 2,5*<maximum size of vm disk>.
Therefore, we recommend that you allocate 100-150 GB (+ some space for backup copied) for the root partition. The rest of HDD — for /vm, if you are going to use a local file system as a storage, or for the linux-lvm partition if you use a local LVM as a storage.