From 982d288850aad5949d4da9c69aceac5356b75fe1 Mon Sep 17 00:00:00 2001 From: dfitzmau Date: Fri, 10 Nov 2023 12:20:02 +0000 Subject: [PATCH] OCPBUGS-10640: Added clarification point to disk partition BM doc --- ...allation-user-infra-machines-advanced.adoc | 28 ++++++++----------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/modules/installation-user-infra-machines-advanced.adoc b/modules/installation-user-infra-machines-advanced.adoc index cf1194a15b6e..5a5b40ae43b6 100644 --- a/modules/installation-user-infra-machines-advanced.adoc +++ b/modules/installation-user-infra-machines-advanced.adoc @@ -73,31 +73,25 @@ The `--copy-network` option only copies networking configuration found under `/e [id="installation-user-infra-machines-advanced_disk_{context}"] == Disk partitioning -// This content is not modularized, so any updates to this "Disk partitioning" section should be checked against the module created for vSphere UPI parity in the module file named `installation-disk-partitioning.adoc` for consistency until such time as this large assembly can be modularized. - The disk partitions are created on {product-title} cluster nodes during the {op-system-first} installation. Each {op-system} node of a particular architecture uses the same partition layout, unless the default partitioning configuration is overridden. During the {op-system} installation, the size of the root file system is increased to use the remaining available space on the target device. -There are two cases where you might want to override the default partitioning when installing {op-system} on an {product-title} cluster node: - -* Creating separate partitions: For greenfield installations on an empty -disk, you might want to add separate storage to a partition. This is -officially supported for mounting `/var` or a subdirectory of `/var`, such as `/var/lib/etcd`, on a separate partition, but not both. -+ [IMPORTANT] ==== -For disk sizes larger than 100GB, and especially disk sizes larger than 1TB, create a separate `/var` partition. See "Creating a separate `/var` partition" and this link:https://access.redhat.com/solutions/5587281[Red Hat Knowledgebase article] for more information. -==== -+ -[IMPORTANT] -==== -Kubernetes supports only two file system partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them. +The use of a custom partition scheme on your node could result in {product-title} not monitoring or alerting on some node partitions. If you override the default partitioning, see link:https://access.redhat.com/articles/4766521[Understanding OpenShift File System Monitoring (eviction conditions)] for more information about how {product-title} monitors your host file systems. ==== -* Retaining existing partitions: For a brownfield installation where you are reinstalling {product-title} on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to `coreos-installer` that allow you to retain existing data partitions. +{product-title} monitors the following two filesystem identifiers: + +* `nodefs`, which is the filesystem that contains `/var/lib/kubelet` +* `imagefs`, which is the filesystem that contains `/var/lib/containers` + +For the default partition scheme, `nodefs` and `imagefs` monitor the same root filesystem, `/`. -[WARNING] +To override the default partitioning when installing {op-system} on an {product-title} cluster node, you must create separate partitions. You might want to add a separate storage partition for your containers and container images. For example, by mounting `/var/lib/containers` in a separate partition, the kubelet separately monitors `/var/lib/containers` as the `imagefs` directory and the root file system as the `nodefs` directory. + +[IMPORTANT] ==== -The use of custom partitions could result in those partitions not being monitored by {product-title} or alerted on. If you are overriding the default partitioning, see link:https://access.redhat.com/articles/4766521[Understanding OpenShift File System Monitoring (eviction conditions)] for more information about how {product-title} monitors your host file systems. +If you resized your disk size to host a larger file system, consider creating a separate `/var/lib/containers` partition. This is important for a disk formatted to `xfs`, where a high number of allocation groups might cause CPU time issues. ==== [id="installation-user-infra-machines-advanced_vardisk_{context}"]