In an OEM deployment that requested the creation of a swap
partition via <oem-swap> that swap partition was created
at first boot and was always the last partition on the disk.
This was required because it could not be placed before
any other partition without destroying those partition
contents. This process leaves the system in an inflexible
condition if the storage device can change its geometry
dynamicly as it's the case for SAN systems. The typical
deployment target for OEM images are SAN storage clusters
and it's cumbersome to resize the root partition if swap
is last.
This commit Fixes#1231 and changes the handling of swap if
requested via <oem-swap> as follows:
1. The swap space is created as part of the image build process
and no longer on first boot of the image via dracut code.
This increases the size of the non compressed .raw disk image
by the configured swap space size or the default. The
compressed versions are not affected since zero initialized
swap space compresses to almost no space. Deployment of
the image however also deploys the swap partition which
increases deployment time. For big swap configurations
it's advisable to switch off image verification via
oem-skip-verify. For very big swap configurations it's
also recommended to prevent kiwi from adding them as part
of the image and let them be created on first boot via
a systemd service that e.g places a swap file, or creates
a swap volume when possible such that the fexibility to
resize the rootfs is still available.
2. The setup of the swap space is now explicit. It's no longer
calculated by twice times RAM size because on newer machines
this could lead to huge numbers. Either the kiwi encoded
default swap size applies or the user configured value.
3. LVM based oem disks creates the swap space as logical volume.
The volume is created as part of the image build process
and no longer on first boot. The swap volume at build time
of the image is of a minimal size and gets resized on first
boot.
4. The move of the swap creation into the builder code also
handles swap per configured device persistency schema like
any other devices. This means by default swap is mounted
via by-uuid name and thus also Fixes#1259
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