Minimum Supported Kernel Upgrade with Systemd

[William Harrington]

Systemd 214-216 README:

REQUIREMENTS:

Linux kernel >= 3.0 Linux kernel >= 3.3 for loop device partition support features with nspawn Linux kernel >= 3.8 for Smack support

Systemd 217 README

REQUIREMENTS:

Linux kernel >= 3.7 Linux kernel >= 3.8 for Smack support

Kernel Config Options:

CONFIG_DEVTMPFS
CONFIG_CGROUPS (it is OK to disable all controllers)
CONFIG_INOTIFY_USER
CONFIG_SIGNALFD
CONFIG_TIMERFD
CONFIG_EPOLL
CONFIG_NET
CONFIG_SYSFS
CONFIG_PROC_FS
CONFIG_FHANDLE (libudev, mount and bind mount handling)

Use this when upgrading to Systemd 217

We may want to warn the user to either view the README or insert text during kernel configuration about 3.7/3.8 requirements.

[William Harrington]

For Systemd 226 (From the README):

REQUIREMENTS:

Linux kernel >= 3.11 Linux kernel >= 4.2 for unified cgroup hierarchy support

Kernel Config Options:

CONFIG_DEVTMPFS CONFIG_CGROUPS (it is OK to disable all controllers) CONFIG_INOTIFY_USER CONFIG_SIGNALFD CONFIG_TIMERFD CONFIG_EPOLL CONFIG_NET CONFIG_SYSFS CONFIG_PROC_FS CONFIG_FHANDLE (libudev, mount and bind mount handling)

udev will fail to work with the legacy sysfs layout:

CONFIG_SYSFS_DEPRECATED=n

Legacy hotplug slows down the system and confuses udev:

CONFIG_UEVENT_HELPER_PATH=""

Userspace firmware loading is not supported and should be disabled in the kernel:

CONFIG_FW_LOADER_USER_HELPER=n

Some udev rules and virtualization detection relies on it:

CONFIG_DMIID

Support for some SCSI devices serial number retrieval, to create additional symlinks in /dev/disk/ and /dev/tape:

CONFIG_BLK_DEV_BSG

Required for PrivateNetwork and PrivateDevices in service units:

CONFIG_NET_NS CONFIG_DEVPTS_MULTIPLE_INSTANCES

Note that systemd-localed.service and other systemd units use PrivateNetwork and PrivateDevices so this is effectively required.

Optional but strongly recommended:

CONFIG_IPV6 CONFIG_AUTOFS4_FS CONFIG_TMPFS_XATTR CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL CONFIG_SECCOMP CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)

Required for CPUShares= in resource control unit settings

CONFIG_CGROUP_SCHED CONFIG_FAIR_GROUP_SCHED

Required for CPUQuota= in resource control unit settings

CONFIG_CFS_BANDWIDTH

For systemd-bootchart, several proc debug interfaces are required:

CONFIG_SCHEDSTATS CONFIG_SCHED_DEBUG

For UEFI systems:

CONFIG_EFIVAR_FS CONFIG_EFI_PARTITION

[William Harrington]

I upgraded the kernel to 4.1 for longevity, but it seems that people who will want unified cgroup hierarchy support will need the 4.2 kernel. I suggest leave the kernel at 4.1 and let the users follow the README.

[William Harrington]

Systemd 233 now requires:

Kernel >= 3.13.x or >= 4.2 for unified cgroup hierarchy support

Review requirements at ​https://github.com/systemd/systemd/blob/master/README

[William Harrington]

Fixed at commit 6a33e9d88e514f1c508cc78d01b9bed2931bec40