Just come across the below - we have 3 unprivileged containers that replicate/pull data over SSH, every 10 seconds or so.  Not directly related to Proxmox itself, but just in case any one else is seeing this.
https://github.com/systemd/systemd/issues/8015
Tried setting 'features: nesting=1' in /etc/pve/lxc/xxx.conf, did not seem to help. Containers running Ubuntu 16.04, with the below systemd:
	
	
	
		
Above github bug report shows issues in later versions also.
				
			https://github.com/systemd/systemd/issues/8015
Tried setting 'features: nesting=1' in /etc/pve/lxc/xxx.conf, did not seem to help. Containers running Ubuntu 16.04, with the below systemd:
		Code:
	
	systemd --version
systemd 229
+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDNAbove github bug report shows issues in later versions also.
 
	