SOLVED [CPANEL-22645] Shells spawned via cPanel Terminal inherit memory limits from cpsrvd

seb.witt

Member
Oct 21, 2018
5
0
1
Germany
cPanel Access Level
Root Administrator
Hello, our webhost directed us here since he was out of ideas as well, so let me try to sum up what is happening.
If you need anything else, please let me know.

So, the issue arises using composer from within cpanel terminal
It not happens via whm terminal and using 'su user' to execute the command. But we need to have this available in cpanel

The command in question, with any package
Code:
composer require package/package --profile
I know this consumes a lot of memory. Once executed we get
Code:
[123.2MB/8.52s] Using version ^2.1 for buzz/laravel-google-captcha
[123.3MB/8.53s] ./composer.json has been updated
[125.2MB/8.75s] Loading composer repositories with package information
[125.4MB/9.11s] Updating dependencies (including require-dev)
mmap() failed: [12] Cannot allocate memory
mmap() failed: [12] Cannot allocate memory
Fatal error: Out of memory (allocated 591405056) (tried to allocate 4096 bytes) in phar:///opt/cpanel/composer/bin/composer/src/Composer/DependencyResolver/Solver.php on line 220
Looking at the top command while executing this, I see the memory jumps max up to 20%, but the cpu hits 100%, so I guess the process gets killed.

What we tried
- Shell fork bomb protection is off. Tried enabling and higher/lower the values, the error stays the same, always killed of at 591405056
- manually adding the values, same as fork bomb protection
- Adjusting the pam values in /etc/security/limits.conf. Doesnt's seem to have any effect though
- Higher the php memory limit, to no effect, setting to -1 with php -d memory_limit=-1 composer.....
The php cli shouldn't have any limit to begin with if i'm not wrong though
- Switching between all kind of mpm for apache with different php handlers and modules, all to no avail

System info
1) Cpanel 74.0 (build 9)
2) CENTOS 7.5 virtuozzo
3) Kernel 2.6.32-042stab125.5
4) As you see we on openvz vps, with no swap for ram, host doesn't allow switching to vswap
5) 4gb ram ( 4 processors Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz )
6) Apache mpm_event with php-fpm and currently for testing purpose without OPcache

ulimit -a in whm
Code:
[/COLOR][/FONT][/LEFT]
core file size                   (blocks, -c) 0
data seg size                   (kbytes, -d) unlimited
scheduling priority           (-e) 0
file size                           (blocks, -f) unlimited
pending signals                (-i) 385882
max locked memory         (kbytes, -l) 64
max memory size             (kbytes, -m) unlimited
open files                         (-n) 1024
pipe size                          (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size                        (kbytes, -s) 10240
cpu time                          (seconds, -t) unlimited
max user processes          (-u) 385882
virtual memory                 (kbytes, -v) unlimited
file locks                           (-x) unlimited

ulimit -a in cpanel
Adjusting this via /etc/profile not allows a higher limit than 786432 for memory
Code:
core file size                  (blocks, -c) 0
data seg size                  (kbytes, -d) unlimited
scheduling priority           (-e) 0
file size                           (blocks, -f) unlimited
pending signals                (-i) 385882
max locked memory         (kbytes, -l) 64
max memory size             (kbytes, -m) 786432
open files                         (-n) 1024
pipe size                          (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority               (-r) 0
stack size                         (kbytes, -s) 10240
cpu time                           (seconds, -t) unlimited
max user processes           (-u) 385882
virtual memory                 (kbytes, -v) 786432
file locks                           (-x) unlimited
[/COLOR][/FONT][/LEFT]

free -m
Code:
[LEFT][FONT=Verdana][COLOR=rgb(85, 85, 85)]              total        used        free      shared  buff/cache   available
Mem:      4096        1167         902         133        2026        2783
Swap:     0           0           0[/COLOR][/FONT][/LEFT]

ipcs -lm
Code:
[LEFT][FONT=Verdana][COLOR=rgb(85, 85, 85)]------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 32768
max total shared memory (kbytes) = 8388608
min seg size (bytes) = 1[/COLOR][/FONT][/LEFT]

Thank you, seb
 

seb.witt

Member
Oct 21, 2018
5
0
1
Germany
cPanel Access Level
Root Administrator
Can someone at least confirm if this an intended feature, or something undocumented?
This only happens in the cpanel terminal and not your regular ssh client. ( tested on 2 different vps with different setups )
Also doesn't seem to be affected by the tweak settings Max cPanel process memory (Minimum: 768)
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,911
2,234
363
Hello @seb.witt,

Internal case CPANEL-22645 was opened to address an issue where cPanel >> Terminal inherit memory limits from cpsrvd. I'll monitor this case and update this thread once the solution is published. In the meantime, the temporary workaround is to access SSH via a third-party client (or the operating system's built-in client). Alternatively, you can temporarily increase the Max cPanel process memory value in WHM >> Tweak Settings.

Thank you.
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,911
2,234
363
Hello,

cPanel & WHM version 76.0.1 is now published to the EDGE and CURRENT release tiers. Included with this build is a solution to the issue reported on this thread:

Fixed case CPANEL-22645: Fix memory limits for shells spawned within cPanel.

The full change log is available here.

Thank you.