noob, multiple doubts

kokoticek

Active Member
Jun 7, 2010
121
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Hello, I'm beginning using proxmox and looks very promising tool but some starter doubts arouse. Hope this is the right section to ask.

1) even after reading around here I still cant understand difference between stopping and shutting down a kvm

2) speaking about stop/shutdown, Ive noticed sometimes shutting down doesn't work, I get a timeout. I have Centos 7, Debian 8 and Windows 10 guest kvms. Cannot remember right now which one gave error, sorry, but I'd like to know because I think it's not always practical to log in each kvm guest and manually shutting down, is it?

3) if a proxmox node is given order to shutdown from the browser gui and there are still kvms turned on, what happens to these? Are they correctly turned off someway, or something bad happens?

4) is difference between clonning and backup/restore indeed just and only the middle step of creating a new vm beforehand for the later case?

5) the task logs in the bottom part of gui window seem to be always in utc. Is it that these logs read server's RTC, which is indeed in utc unlike server's system time?

6) if using firefox browser, can it be bad/risky to forget to log out before closing the browser? Even if logged as root? If so, what can I do to fix? I beg it's not to reinstall whole proxmox...........
 
Hello, I'm beginning using proxmox and looks very promising tool but some starter doubts arouse. Hope this is the right section to ask.

1) even after reading around here I still cant understand difference between stopping and shutting down a kvm
Hi,
shutting down use acpi to tell the VM-guest to shutdown... stopping is more pull the power plug ;-)
2) speaking about stop/shutdown, Ive noticed sometimes shutting down doesn't work, I get a timeout. I have Centos 7, Debian 8 and Windows 10 guest kvms. Cannot remember right now which one gave error, sorry, but I'd like to know because I think it's not always practical to log in each kvm guest and manually shutting down, is it?
acpi must be enabled to shutdown the VM - see here: http://pve.proxmox.com/wiki/Acpi_kvm
3) if a proxmox node is given order to shutdown from the browser gui and there are still kvms turned on, what happens to these? Are they correctly turned off someway, or something bad happens?
after an timeout (afaik 3min) the VMs will be killed - what sould pve do, if the clients don't stop?!
4) is difference between clonning and backup/restore indeed just and only the middle step of creating a new vm beforehand for the later case?

5) the task logs in the bottom part of gui window seem to be always in utc. Is it that these logs read server's RTC, which is indeed in utc unlike server's system time?
hmm, no - my task-logs are not utc...
How looks timedatectl on your host?
Code:
root@pve1:~# timedatectl
  Local time: Mon 2016-08-08 23:39:11 CEST
  Universal time: Mon 2016-08-08 21:39:11 UTC
  RTC time: Mon 2016-08-08 21:39:11
  Time zone: Europe/Berlin (CEST, +0200)
  NTP enabled: no
NTP synchronized: yes
 RTC in local TZ: no
  DST active: yes
 Last DST change: DST began at
  Sun 2016-03-27 01:59:59 CET
  Sun 2016-03-27 03:00:00 CEST
 Next DST change: DST ends (the clock jumps one hour backwards) at
  Sun 2016-10-30 02:59:59 CEST
  Sun 2016-10-30 02:00:00 CET
6) if using firefox browser, can it be bad/risky to forget to log out before closing the browser? Even if logged as root? If so, what can I do to fix? I beg it's not to reinstall whole proxmox...........
your ticket isn't valid for the next browser start - so you must login again.

Udo
 
Thanks for the help!

2) wait, so Centos 7 and Debian 8 minimal installations don't include acpi default enabled? I thought they did! What about Windows 10, do I need to install an additional driver for it as well?

3) even in production environments I think there should be times when a node needs to be powered off, no? Doesn't Proxmox have some kind of control to "nicely" use shutdown (not stop) function on all guests when a poweroff signal is issued on a node?

4) is difference between clonning and backup/restore indeed just and only the middle step of creating a new vm beforehand for the later case? I think we missed this point...

5) in my host it looks just like yours do (with the respective changes according to timezone, of course), except for only one difference: I have "NTP enabled: yes" instead, but this is how Proxmox 4.2 installed by default...

By the way, just for info, I did install latest Proxmox 4.2, and already did "apt update && apt full-upgrade".
 
2) wait, so Centos 7 and Debian 8 minimal installations don't include acpi default enabled? I thought they did! What about Windows 10, do I need to install an additional driver for it as well?
AFAIK, no these distribtions do not include acpi by default,
For Windows 10, i think the steps in the ACPI kvm wiki entry still apply, but i am not sure.

Alternatively, you can install the qemu-guest-agent (after enabling it in the options tab of the vm)
see https://pve.proxmox.com/wiki/Qemu-guest-agent

after installing this, we use the guest agent to initiate a graceful shutdown of the guest

3) even in production environments I think there should be times when a node needs to be powered off, no? Doesn't Proxmox have some kind of control to "nicely" use shutdown (not stop) function on all guests when a poweroff signal is issued on a node?
It works like this:

All VMs get a Shutdown signal (either acpi or qemu-guest-agent) in the reverse bootorder (so the last vm to boot is the first to shutdown)
If this times out after (i think) 3 minutes, we send a "kill" signal to the kvm process (otherwise the shutdown would be blocked forever)

4) is difference between clonning and backup/restore indeed just and only the middle step of creating a new vm beforehand for the later case? I think we missed this point...
no, cloning just clones the disks to the target storage and copies the configuration.

a backup creates a backup file in our special "vma" format, which includes all disks and configuration in a single file.
 
Regarding this again,

5) the task logs in the bottom part of gui window seem to be always in utc. Is it that these logs read server's RTC, which is indeed in utc unlike server's system time?

I set timedatectl in proxmox host just like @udo has, still have the issue. I use firefox browser to access proxmox interface and do all the stuff and have tried in 2 pcs a windows one and a linux one. The only thing I could think about was the fact that both machines curiously use the rtc in local time, while proxmox node uses rtc in utc (but system time in local indeed). But beyond this no idea at all.

Any further help? thanks.
 
Issue 5) is still pendant (please...), but meanwhile I stumbled with different doubts.
Just to clarify, I just have one node server for now.

7) the node has cpu intel xeon 4 cores 3.1 GHz and 10 Gb RAM. Proxmox installer seemingly left 8 Gb swap partition by looking at node's summary in proxmox interface. I tried turning on 4 kvms at a time (each one with cpu one socket, 2 cores): 3 linux vms with ram 512/1 Gb balloon and 1 win10 vm with ram 2Gb/3Gb balloon, leaving all 4 just iddle. None of them reached 25% ram usage and cpu usage was low as well.
Then took a look at node's summary in proxmox interface (and also tried command "top" in the node itself just to compare). What the hell!!?? Circa all physical ram was being used, and even nearly half of the swap partition, while cpu usage was in appearance minimal!!! Average cpu usage was I think around 1 or 2%...

8) can a same user log in into a same proxmox node but from 2 different pcs? If for some reason answer was positive, what could happen if same user in same node from different pcs at one time tried to use the same vm?

thanks again.
 
as to 5) no idea, i have here the tasks timestamps with the local time, with rtc set to utc
did you restart the host or the services after you set the local time?

7) do you use zfs?
if not, what processes use the ram? (in top you can sort by memory using the "f" key then select memory and the press "s")
also what does the command "free -h" say?

8) yes you can log in multiple times
if by "use" you mean use the console, then with vms all would see the same
 
@dcsapak :

7) proxmox interface shows me what appear to be 2 partitions: one smaller "normal" one where data such as backups, isos, etc are stored; and one bigger lvm one which seems totally unwrittable by users (not even root) and where VMs themselves are stored. When checking proxmox node itself it seems it can only see the small partition, which is ext4. So I don't think, or rather I have no way to tell if zfs -whatever it is- is being used. Hey, I installed proxmox in general just by taking defaults!
Regarding the ram issues, heck, I was not able to replicate the issue, it's as if it had "magically" fixed by itself or don't know, which is FRUSTRATING. Instead, I have a smaller issue: now proxmox node and proxmox web interface show different results regarding ram usage (though not cpu usage). Though both show no swap usage, interface shows 4.6 Gb ram used, while in proxmox node both top and free -h show 7 Gb ram used, though these later also show 2.3 Gb used for something called "buffer"...
Regarding the ram usage sorting, assuming on top is the one using more ram, I only see like 8 processes using ram, all of them just summing 40% used -what the heck?-, being the first command "kvm and" the only one using like 31%, the rest being commands kvm or pveproxy w+.
Nevertheless, I still think proxmox node is still consuming way more ram than expected considering the description of each kvm in terms of ram I gave in my previous post (in fact, 2 linux vms actually don't even actually reach 15% used ram).

8) I'm a bit surprised with the mutliple logins thing to begin with... I think the actual question then would be, what could happen if *more* than one user try to use the very same VM in the same node at the same time? That's be like a pc having multiple keyboard-mouse pairs trying to process contradicting sets of different orders at once! What the heck? That should explode the pc to begin with!
 
8) I'm a bit surprised with the mutliple logins thing to begin with... I think the actual question then would be, what could happen if *more* than one user try to use the very same VM in the same node at the same time? That's be like a pc having multiple keyboard-mouse pairs trying to process contradicting sets of different orders at once! What the heck? That should explode the pc to begin with!
Hi,
why should this be an problem? You really know very fast, if another work on an VM-console too. The battle of the cursor start ;-)
(it's not more keyboard/mouse - it's mixed input)

And you see in the task-list who has open the console (not very helpfull if all use the same account).
This is also nice to teach someone at any problem - you can look first and take the control if both play the same game.
Or, if you use one console for remote-access - you can see was the remote people do with your system!

Udo
 
Thanks. (Though still sounds a bit weird...)

Regarding point 7) about the ram, any ideas about it? I'm still doubtful...
 
to 7)

linux always tries to use unused memory for its buffer/cache, this is normal behaviour
this is a point which is often raised from people who come from windows.

windows does the same, but reports the memory it uses for buffer/cache as free, in contrast to linux where it is "used"

we show the "real" used value in the webgui, so we do not count buffers/cache
 
@dcsapak:

Thanks very much sir; though I actually meant the part:
"Nevertheless, I still think proxmox node is still consuming way more ram than expected considering the description of each kvm in terms of ram I gave in my previous post (in fact, 2 linux vms actually don't even actually reach 15% used ram)."
 
okay well looking at the things you wrote, you have 3 vms with minimum 512MB and 1 with minimum 2GB which makes (3*512)+2048 = 3584 MB which are always reserved, regardless of how much the vms use.
adding a little bit for the host, and you come to about 4 to 4.5 GB of used memory.

Looks normal
 
acpi must be enabled to shutdown the VM - see here: http://pve.proxmox.com/wiki/Acpi_kvm

Udo, I followed your advice and tried installing acpid in a Debian8 LXC with the following result:
Code:
apt-get install acpid -u
.
.
.
Setting up acpid (1:2.0.23-2) ...
insserv: warning: script 'K01nixstats' missing LSB tags and overrides
insserv: warning: script 'nixstats' missing LSB tags and overrides
Starting ACPI services...RTNETLINK1 answers: No such file or directory
acpid: error talking to the kernel via netlink
.
Setting up acpi-support-base (0.142-6) ...
RTNETLINK1 answers: No such file or directory
acpid: error talking to the kernel via netlink

Is this some easy fix or should I open another thread?


###edit###Sorry, I noticed I'm talking about a LXC while the link you posted was for KVM :-( I guess I don't need acpi.
 
Last edited:
As I stated since this post's title, I am nothing but a novice, so I still don't know anything about LXC. But at least for a KVM, a Debian 8 minimal installation (though at least including the standard system utilities package; don't know about Ubuntu...) already includes the acpi package. But indeed a Centos 7 minimal installation does not and must be installed. Windows 10 also includes already an acpi driver -haven't tried 8.1 or 7...- though it has a small issue to consider: if the Windows 10 vm is already "asleep" (suspension/hibernation/the like) the shutdown button in proxmox interface will only serve to "wake up" the vm but won't actually shut it down, and as such proxmox will give a timeout error for the command. One must first wake the vm up then shutdown.

Perhaps someone could update the wiki page https://pve.proxmox.com/wiki/Acpi_kvm with this little info?
 
@dcsapak:

Didn't work! I tried changing the balloon range for the win10 vm to 512 min, 3 Gb max, started the vm, left it idle and waited until its ram consumption lowered to some 700 Mb used, checked proxmox summary, and it still says node it's comsuming 3.8 Gb ram!! While with no active vms node is just using 700-800 Mb ram!
 

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