Basic guidance
The following table provides basic cluster infrastructure guidance. For detailed configuration information, see Cluster Hardware Design. Administrators can build a container cluster to be deployed quickly and reliably when each node is within the validated design guidelines.
Table 1. Hardware infrastructure for OpenShift Container Platform 4.3 cluster deployment
CSAH node |
Dell EMC PowerEdge R640 server |
1 |
Creates a bootstrap node. The bootstrap node is later converted to a worker node. CSAH runs a single instance of HAProxy. For enterprise high availability (HA) deployment of OpenShift Container Platform 4.3, Dell Technologies recommends using a commercially supported L4 load-balancer or proxy service or system. Options include: Commercial HAProxy, Nginx, F5, or other. |
Master nodes |
Dell EMC PowerEdge R640 server |
3 |
Deployed using the bootstrap node. |
Worker nodes |
Dell EMC PowerEdge R640 or R74EMC 0xd server |
Minimum 3, maximum 30 per rack |
One of the worker nodes is initially deployed as the bootstrap node and can later be repurposed as a worker node. At least two worker nodes are required to build a cluster; after two worker nodes are operational, the bootstrap node can be repurposed as a worker node. After the cluster is operational, you can add more worker nodes to the cluster through the Cluster Management Service. |
Data switches |
Either of the following switches:
- Dell EMC PowerSwitch S5248-ON
- Dell EMC PowerSwitch S5232-ON
|
2 per rack |
Autoconfigured at installation time. Note:
- HA network configuration requires 2 data path switches per rack.
- Multi-rack clusters require network topology planning. Leaf-spine network switch configuration may be necessary.
|
iDRAC network |
Dell EMC PowerSwitch S3048-ON |
1 per rack |
Used for OOB management. |
Rack |
Selected according to site standards |
1 to 3 racks |
For multi-rack configurations, consult your Dell Technologies or Red Hat representative regarding custom engineering design. |
Installing OpenShift Container Platform requires, at a minimum, the following nodes:
- One CSAH node, which is used to install the bootstrap node. The CSAH node is used later to manage the cluster while the cluster is in production use.
- One bootstrap machine, which is used to deploy the OpenShift Container Platform cluster on the three master nodes. You can repurpose the bootstrap node after the cluster is installed.
- Three control plane (or master) nodes.
- At least two compute (or worker) nodes.
High availability (HA) of the key services that make up the OpenShift Container Platform cluster is necessary to ensure run-time integrity. Redundancy of physical nodes for each cluster node type is an important aspect of HA for the bare-metal cluster.
In this design guide, HA includes the provisioning of at least dual network adapters and dual network switches that are configured to provide redundant pathing. The redundant pathing provides for network continuity if a network adapter or a network switch fails.
OpenShift Container Platform 4.3 must use Red Hat Enterprise Linux CoreOS (RHCOS) for the control plane (master) machines and can use either RHCOS or Red Hat Enterprise Linux 7.6 for compute (worker) machines. The bootstrap and master nodes must use RHCOS as their operating system. Each of these nodes must be immutable.
The following table shows the minimum resource requirements:
Table 2. Minimum resource requirements for OpenShift Container Platform 4.3 nodes
CSAH |
Red Hat Enterprise Linux 7.6+ |
4 |
32 GB |
200 GB |
Bootstrap |
RHCOS 4.3 |
4 |
16 GB |
120 GB |
Master |
RHCOS 4.3 |
4 |
16 GB |
120 GB |
Worker |
RHCOS 4.3 or Red Hat Enterprise Linux 7.6 |
2 |
8 GB |
120 GB |
The RHCOS nodes must fetch ignition files from the Machine Config server. This operation makes use of initial network configuration using an initramfs-based-node startup. The initial startup requires a DHCP server to provide a network connection to give access to the ignition files for that node. Subsequent operations can use static IP addresses.
