Running any of the commands varnishstat, varnishhist, varnishlog, varnishtop will give the error message as
Could not get hold of varnishd, is it running?
Below is some information for understanding.
sudo service varnish status
varnish.service - Varnish Cache, a high-performance HTTP accelerator
Loaded: loaded (/lib/systemd/system/varnish.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2017-11-15 15:28:04 UTC; 1h 16min ago
Process: 10235 ExecStart=/usr/sbin/varnishd -a :80 -T localhost:6082 -f /etc/varnish/default.vcl -S /etc/varnish/secret -s malloc,256m (code=ex
Main PID: 10251 (varnishd)
Tasks: 217
Memory: 106.2M
CPU: 1.673s
CGroup: /system.slice/varnish.service
├─10251 /usr/sbin/varnishd -a :80 -T localhost:6082 -f /etc/varnish/default.vcl -S /etc/varnish/secret -s malloc,256m
└─10271 /usr/sbin/varnishd -a :80 -T localhost:6082 -f /etc/varnish/default.vcl -S /etc/varnish/secret -s malloc,256m
Nov 15 15:28:03 varnish1 systemd[1]: Starting Varnish Cache, a high-performance HTTP accelerator...
Nov 15 15:28:04 varnish1 varnishd[10235]: Debug: Platform: Linux,4.11.0-1014-azure,x86_64,-junix,-smalloc,-smalloc,-hcritbit
Nov 15 15:28:04 varnish1 varnishd[10251]: Platform: Linux,4.11.0-1014-azure,x86_64,-junix,-smalloc,-smalloc,-hcritbit
Nov 15 15:28:04 varnish1 varnishd[10235]: Debug: Child (10271) Started
Nov 15 15:28:04 varnish1 varnishd[10251]: Child (10271) Started
Nov 15 15:28:04 varnish1 varnishd[10251]: Child (10271) said Child starts
Nov 15 15:28:04 varnish1 systemd[1]: Started Varnish Cache, a high-performance HTTP accelerator.
sudo service varnishd status
varnishd.service
Loaded: not-found (Reason: No such file or directory)
Active: inactive (dead)
sudo service varnishd start
Failed to start varnishd.service: Unit varnishd.service not found.
varnishd -V
varnishd (varnish-5.2.1 revision 67e562482)
Copyright (c) 2006 Verdens Gang AS
Copyright (c) 2006-2015 Varnish Software AS
Answer:
sudo varnishstat
sudo varnishhist
sudo varnishlog
sudo varnishtop