Knowledge Base

Pagespeed does not optimize static files and throws errors in Apache logs

Symptoms

There are no optimized static files on the website with the Pagespeed Insights extension installed in Plesk:

Browser DevTools (F12) -> Network tab shows normal files without changes in their names. For example, when checking website URL like this:

https://example.com/?PageSpeedFilters=debug,rewrite_images,rewrite_css,rewrite_javascript:
CentOS 7 with kernel version 3.10.0-*** is installed on the server:

# uname -msr
Linux 3.10.0-957.1.3.el7.x86_64 x86_64
On website request, the following errors appear in /var/log/httpd/error.log

[pagespeed:error] [pid 17686:tid 140535759107840] [mod_pagespeed 1.13.35.2-0 @17686] Failed to mkdir /var/cache/mod_pagespeed/ flush /jb9Xrf3F7w4hZ6Y_MmFT.outputlock: No such file or directory
[pagespeed:error] [pid 17686:tid 140535759107840] [mod_pagespeed 1.13.35.2-0 @17686] Failed to mkdir /var/cache/mod_pagespeed/ flush /rc:rname/ic_2L-ZMDIrHfcg3SV5sQCm/http://203.0.113.2/favicon.ico@x@._: No such file or directory
On Apache restart the following [pagespeed] errors and warnings appear in /var/log/httpd/error.log:

[pagespeed:error] [pid 4142:tid 139973393344640] [mod_pagespeed 1.13.35.2-0 @4142] Unable to create SHM segment [1]globalstatistics, mmap failed with errno=13.
[pagespeed:warn] [pid 4142:tid 139973393344640] [mod_pagespeed 1.13.35.2-0 @4142] Problem during shared memory setup; statistics functionality unavailable.

[pagespeed:error] [pid 4142:tid 139973393344640] [mod_pagespeed 1.13.35.2-0 @4142] Unable to create SHM segment [1]globalstatistics, mmap failed with errno=13.
/var/log/audit/audit.log contains denial messages like below:

type=AVC msg=audit(1547191637.807:48051): avc: denied { map } for pid=26035 comm="httpd" path="/dev/zero" dev="devtmpfs" ino=1030 scontext=system_u:system_r:httpd_t:s0 tcontext=system_u:object_r:zero_device_t:s0 tclass=chr_file permissive=0
type=SYSCALL msg=audit(1547191637.807:48051): arch=c000003e syscall=9 success=no exit=-13 a0=0 a1=48000 a2=3 a3=1 items=0 ppid=1 pid=26035 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="httpd" exe="/usr/sbin/httpd" subj=system_u:system_r:httpd_t:s0 key=(null)