Unknown tmpfs filesystems mounted under /run/credentials post patching

SUSE Linux Enterprise for SAP Applications 15

SUSE Linux Enterprise Server 15

Multiple unknown tmpfs filesystems mounted under /run/credentials directory post patching,

tmpfs                      1.0M     0  1.0M   0% /run/credentials/systemd-tmpfiles-setup-dev-early.service
tmpfs                      1.0M     0  1.0M   0% /run/credentials/systemd-tmpfiles-setup-dev.service
tmpfs                      1.0M     0  1.0M   0% /run/credentials/systemd-vconsole-setup.service
tmpfs                      1.0M     0  1.0M   0% /run/credentials/systemd-tmpfiles-setup.service
tmpfs                      1.0M     0  1.0M   0% /run/credentials/getty@tty1.service

These files are created for tmpfs mountpoints for systemd service. 

# mount | grep systemd-
tmpfs on /run/credentials/systemd-tmpfiles-setup-dev-early.service type tmpfs (ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap)
tmpfs on /run/credentials/systemd-sysctl.service type tmpfs (ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap)
tmpfs on /run/credentials/systemd-tmpfiles-setup-dev.service type tmpfs (ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap)
tmpfs on /run/credentials/systemd-vconsole-setup.service type tmpfs (ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap)
tmpfs on /run/credentials/systemd-tmpfiles-setup.service type tmpfs (ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap)

These are OS related files which should not be removed, unmounted or altered. There is no clean way to permanently unmount them. However we can use exclude option in df command or use below command to exclude systemd tmpfs filesystem mounts from df -h output, similarly we can set the alias as well.

# df -h | grep -v service

This behavior is observed starting with systemd-254.23-150600.4.25.1.x86_64 version in SUSE Linux Enterprise for SAP Applications 15 SP6.

According to the man page, 

System and Service Credentials are data objects that may be passed into booted systems or system services as they are invoked. They can be acquired from various external sources, and propagated into the system and from there into system services. Credentials may optionally be encrypted with a machine-specific key and/or locked to the local TPM2 device, and are only decrypted when the consuming service is invoked.

System credentials may be used to provision and configure various aspects of the system. Depending on the consuming component credentials are only used on initial invocations or are needed for all invocations.

Credentials may be used for any kind of data, binary or text, and may carry passwords, secrets, certificates, cryptographic key material, identity information, configuration, and more.

Filesystem mounts under /run often serve critical functions, and disabling or unmounting them can lead to serious problems.

For more information please check below links,

https://www.freedesktop.org/software/systemd/man/devel/systemd.system-credentials.html

https://systemd.io/CREDENTIALS/