From ee79729dc68994bca5727bbedb22194f60799bee Mon Sep 17 00:00:00 2001 From: Christian Goll Date: Mon, 1 Jul 2024 10:58:05 +0200 Subject: [PATCH] updated documenation regarding fswipe Signed-off-by: Christian Goll --- userdocs/contents/disks.rst | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/userdocs/contents/disks.rst b/userdocs/contents/disks.rst index bc521eba..176e3857 100644 --- a/userdocs/contents/disks.rst +++ b/userdocs/contents/disks.rst @@ -46,7 +46,7 @@ Each partition is identified by its label. The partition number can be omitted, but specifying it is recommended as ``ignition`` may fail without it. Partition sizes should also be set (specified in MiB), except of the last partition: if no size is given, the maximum available size is used. -Each partition has the switches ``should_exist`` and ``wipe_partition_entry`` which control the partition creation process. +Each partition has the switches ``should_exist`` and ``wipe_partition_entry`` which control the partition creation process. When omitting a partition number the `wipe_partition_entry` should be true, as this allows ignition to replace the existing partition. File systems are identified by their underlying block device, preferably using the ``/dev/by-partlabel`` format. Except for a ``swap`` partition, an absolute path for the mount point must be specified for each file system. @@ -73,8 +73,8 @@ The following command will create a ``/scratch`` file system on the node ``n01`` wwctl node set n01 \ --diskname /dev/vda --diskwipe \ - --partname scratch --partcreate \ - --fsname scratch --fsformat btrfs --fspath /scratch --fswipe + --partname scratch --partcreate --partnumber 1 \ + --fsname scratch --fsformat btrfs --fspath /scratch As this is a single file system, the partition number can be omitted. @@ -84,12 +84,29 @@ A swap partition with 1Gig can be added with wwctl node set n01 \ --diskname /dev/vda \ - --partname swap --partsize=1024 --partnumber 1 \ + --partname swap --partsize=1024 --partnumber 2 \ --fsname swap --fsformat swap --fspath swap which has the partition number ``1`` so that it will be added before the ``/scratch`` partition. +Wiping disks +============ + +Unless you specify the `--fswipe` flag for a filesystem, `ignition` will try to +reuse existing file systems. For empty disks this means that the desired configuration +is created and the filesystems are mounted; and so the `--fswipe` can be omitted so +data is on the disk isn't wiped. +If there are pre-existing partitions and filesystem on the disk, omitting the `--fswipe` may lead to the outcome that no filesystems are created and mounted. +In that case you should: +* wipe the existing data with the means of tools like `wipefs` or `dd` [#] +* set the `--fswipe` flag and remove it after one reboot, if you want to keep +existing data on the disk. + +.. [#] With `wipefs` you have to remove the filesystem *and* parition information. E.g. use `wipefs -fa /dev/vda*` to remove all filesystem information and partition information. + +See also [ignition documentation](https://coreos.github.io/ignition/operator-notes/#filesystem-reuse-semantics) for additional information. + Troubleshooting ===============