PVE 5.2 LXC guest - Summary: CPU and Memory readings zeroed after adding a mount point

[Marco Trevisan]

Hi all,

First and foremost: my congratulations on this excellent virtualization environment. I've been using it for years and I'm suggesting it to everyone who asks me an opinion on what good hypervisor to use.
Maybe I'm not a noob on ProxMox, but I'm not a super hacker either.

As the summary hopefully explains, I'm facing a weird behaviour.

• In one CT I mounted a NFS mount point using the GUI, resulting in a raw file in the NFS share to be used by the guest.
• In another CT I did a bind mount, as explained elsewhere in the forums, resulting in a 1:1 file/directory relationship between the guest and the nfs share, which is going to host up to 3 TB of Maildirs.

So far so good, everything works and looks good, as far as a high level view is concerned.

The only strange thing is that the CPU and RAM readings in the Summary view (of those two guests) are almost zeroed. I mean:

• RAM usage shows some megabytes instead of almost 1 GB.
• CPU usage shown is zero, constantly.

If I run a "top" in the guest I see my expected results, so it's a minor problem for me.

My guess is that something is going wrong while processing the conf file for those guests because of the mp declaration, and the container brings up the guests without access to CPU and RAM readings.

arch: amd64
cores: 4
hostname: modoboa
memory: 2048
mp0: /mnt/pve/mbox/mailboxes,mp=/mnt/mbox,shared=1,replicate=0
nameserver: my.dns.ip.addr
net0: name=eth0,bridge=vmbr1,gw=my.gw.ip.addr,hwaddr=aa:bb:cc:dd:ee:ff,ip=my.ip.lan.net/24,tag=8,type=veth
onboot: 1
ostype: debian
rootfs: local-zfs:subvol-110-disk-0,size=10G
swap: 4096
unprivileged: 1

Any help or hint is appreciated.

Kind regards,
Marco

 

[wolfgang]

Hi,

this is absolut possible.
Lests say you have a Mail server with a DB backend but on this email server you get only all hours one EMail so the DB needs Memory for the tables but has nothing to do because nothing happened.

But you can check this if you run top in the CT and on the host you can verify this with "systemd-cgls" "systemd-cgtop" and ps

 

[Marco Trevisan]

Hi Wolfgang,
thank you very much for your reply.
The output of systemd-cgtop is as follows:

Control Group                                             Tasks   %CPU   Memory  Input/s Output/s
/                                                            88    1.1     1.1G        -        -
/user.slice                                                   5    1.1     6.0M        -        -
/user.slice/user-0.slice                                      5    1.1     5.7M        -        -
/user.slice/user-0.slice/session-9913.scope                   3    1.1     3.8M        -        -
/init.scope                                                   1      -     2.7M        -        -
/system.slice                                                82      -     1.7M        -        -
/system.slice/amavis.service                                  2      -        -        -        -
/system.slice/clamav-daemon.service                           2      -        -        -        -
/system.slice/clamav-freshclam.service                        1      -        -        -        -
/system.slice/console-getty.service                           1      -        -        -        -
/system.slice/cron.service                                    1      -        -        -        -
/system.slice/dbus.service                                    1      -        -        -        -
/system.slice/dovecot.service                                13      -        -        -        -
/system.slice/memcached.service                               7      -        -        -        -
/system.slice/nginx.service                                   9      -        -        -        -
/system.slice/opendkim.service                                7      -        -        -        -
/system.slice/rpcbind.service                                 1      -        -        -        -
/system.slice/rsyslog.service                                 3      -        -        -        -
/system.slice/ssh.service                                     1      -        -        -        -
/system.slice/supervisor.service                              2      -        -        -        -
/system.slice/system-container\x2dgetty.slice                 2      -        -        -        -
/system.slice/syst…etty.slice/container-getty@1.service       2      -        -        -        -
/system.slice/system-postfix.slice                           10      -        -        -        -

Output of "top":

top - 10:42:37 up 1 day, 16 min,  2 users,  load average: 0.28, 0.29, 0.32
Tasks:  71 total,   1 running,  70 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.3 us,  0.2 sy,  0.0 ni, 99.4 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  2097152 total,   923800 free,  1110640 used,    62712 buff/cache
KiB Swap:  6291456 total,  6291456 free,        0 used.   986512 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                           
29831 root      20   0   41188   2532   1896 R   0.3  0.1   0:00.28 top                                               
    1 root      20   0   57036   5764   4208 S   0.0  0.3   0:01.12 systemd                                           
   74 root      20   0   49876   2588   2156 S   0.0  0.1   0:00.10 rpcbind                                           
  123 clamav    20   0  152612  19440  14900 S   0.0  0.9   0:26.72 freshclam                                         
  127 message+  20   0   45136   2640   2200 S   0.0  0.1   0:00.09 dbus-daemon                                       
  133 memcache  20   0  335696   1980   1532 S   0.0  0.1   0:14.63 memcached                                         
  134 root      20   0  180484   2432   2036 S   0.0  0.1   0:04.35 rsyslogd                                           
  136 root      20   0   57952  18384   5448 S   0.0  0.9   0:14.42 supervisord                                       
  139 root      20   0   27996   1868   1588 S   0.0  0.1   0:01.57 cron                                               
  156 root      20   0   18136   2104   1764 S   0.0  0.1   0:01.52 dovecot                                           
  158 dovecot   20   0    9496    916    808 S   0.0  0.0   0:00.14 anvil                                             
  159 root      20   0    9628   1868   1576 S   0.0  0.1   0:00.30 log                                               
  162 root      20   0   69948   4204   3452 S   0.0  0.2   0:00.02 sshd                                               
  165 root      20   0   25324   3240   1948 S   0.0  0.2   0:08.26 config                                             
  170 clamav    20   0  923192 587696  19964 S   0.0 28.0   2:04.34 clamd                                             
  173 root      20   0   67772   2568   2048 S   0.0  0.1   0:00.03 login                                             
  175 root      20   0   12672   1224   1088 S   0.0  0.1   0:00.01 agetty                                             
  197 root      20   0  170476   2644    876 S   0.0  0.1   0:00.01 nginx                                             
  201 www-data  20   0  170476   3180   1176 S   0.0  0.2   0:03.74 nginx                                             
  202 www-data  20   0  170476   6040   3880 S   0.0  0.3   0:03.27 nginx                                             
  203 www-data  20   0  170476   6020   3856 S   0.0  0.3   0:03.51 nginx                                             
  204 www-data  20   0  170476   3180   1176 S   0.0  0.2   0:03.74 nginx                                             
  206 www-data  20   0  170476   3180   1176 S   0.0  0.2   0:03.70 nginx                                             
  207 www-data  20   0  170476   3180   1176 S   0.0  0.2   0:03.71 nginx                                             
  211 www-data  20   0  170616   5776   3584 S   0.0  0.3   0:03.24 nginx                                             
  212 www-data  20   0  170476   5792   3600 S   0.0  0.3   0:02.09 nginx

Output of "Top" order by Memory:

%Cpu(s):  0.7 us,  0.1 sy,  0.0 ni, 99.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  2097152 total,   916504 free,  1117940 used,    62708 buff/cache
KiB Swap:  6291456 total,  6291456 free,        0 used.   979212 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                            
  170 clamav    20   0  923192 587696  19964 S   0.0 28.0   2:04.34 clamd                                              
 1249 modoboa   20   0  410232 139880  13420 S   0.0  6.7   0:51.69 uwsgi                                              
  744 amavis    20   0  308136 139608   7664 S   0.0  6.7   0:03.95 /usr/sbin/amavi                                    
 1248 modoboa   20   0  408824 138540  13332 S   0.0  6.6   0:24.13 uwsgi                                              
22519 amavis    20   0  309624 135796   3852 S   0.0  6.5   0:00.00 /usr/sbin/amavi                                    
  559 modoboa   20   0  264072  70172  11380 S   0.0  3.3   0:06.46 uwsgi                                              
 3849 root      20   0   83020  39256  38744 S   0.0  1.9   0:15.42 systemd-journal                                    
  657 radicale  20   0   77032  23512   6072 S   0.0  1.1   0:00.61 radicale                                            
  224 postgres  20   0  285948  21184  19396 S   0.0  1.0   0:11.57 postgres                                            
  389 automx    20   0  137832  20208   8788 S   0.0  1.0   0:02.89 uwsgi                                              
  123 clamav    20   0  152612  19440  14900 S   0.0  0.9   0:26.72 freshclam                                          
  136 root      20   0   57952  18384   5448 S   0.0  0.9   0:14.47 supervisord                                        
  465 automx    20   0  137832  14780   3360 S   0.0  0.7   0:00.00 uwsgi                                              
  467 automx    20   0  137832  14780   3360 S   0.0  0.7   0:00.00 uwsgi                                              
  251 postgres  20   0  286072  13856  11972 S   0.0  0.7   0:00.85 postgres                                            
  290 postgres  20   0  286944  12852  10304 S   0.0  0.6   0:00.05 postgres                                            
  285 postgres  20   0  287544  12584   9944 S   0.0  0.6   0:00.11 postgres                                            
30056 postgres  20   0  286936  12536  10020 S   0.0  0.6   0:00.01 postgres                                            
30057 postgres  20   0  286936  12536  10020 S   0.0  0.6   0:00.01 postgres                                            
30352 postgres  20   0  286936  12536  10024 S   0.0  0.6   0:00.01 postgres                                            
30353 postgres  20   0  286936  12536  10020 S   0.0  0.6   0:00.01 postgres                                            
  294 opendkim  20   0  421532   9576   4924 S   0.0  0.5   0:02.09 opendkim                                            
  253 postgres  20   0  285948   7936   6128 S   0.0  0.4   0:01.40 postgres                                            
30055 dovecot   20   0   76536   6192   5012 S   0.0  0.3   0:00.01 dict                                                
14297 postfix   20   0   87464   6188   5360 S   0.0  0.3   0:00.03 tlsmgr

Summary view in the web control panel is showing 0% CPU, 1.14MB RAM usage, and flat history graphs for CPU and RAM.
Network IO, on the other hand, is showing up regularly in the Summary.

This applies ONLY to the two CT that have a mount point. All the other CTs in the cluster do not have any mp, are on the exact same Debian template (debian 9), and CPU and RAM summary works as expected on them.

As I said, not a real problem for me, just something to let you know.

Best regards,
Marco