How do I see if memcached is already running on my chosen port?

Question

I am having some problems with memcached and one idea I am having is that perhaps it is already running on the port I am trying to run it on, started by some other user on our network. Is there a way to tell what memcached ports are currently in use?

Have you tried connecting to them? Even a denial of access will prove your point. — Dereleased, Nov 06 '09 at 22:43
Also, when I kill my own memcached process with the port I started it on, and try to connect to the port, I do get a denial of access. I am wondering if a process is hanging in some kind of corrupted state and therefore somehow blocking access to the port. — barclay, Nov 06 '09 at 22:54

score 91 · Answer 1 · answered Oct 24 '11 at 19:06

91

To see if it is running you could also try telnetting into the port:

telnet localhost 11211

If this works you will see the following (telling you that the given port is open):

Connected to localhost.
Escape character is '^]'.

Now if memcached IS running you can see some basic stats by issuing the given command:

stats

If this fails you will know that memcached is not running.

answered Oct 24 '11 at 19:06

simoes

4,897
4
23
28

@simoes very nicely written answer. Voted up! – ambodi May 11 '15 at 14:31
4

To exit, just type quit – sandre89 Nov 28 '16 at 14:14
This should be the accepted answer. Well done. – earl3s Apr 20 '21 at 20:51

score 34 · Accepted Answer · edited Sep 04 '14 at 13:02

34

Try

netstat -ap | grep TheChosenPort#

and see if anything is listening on those TCP or UDP ports.

edited Sep 04 '14 at 13:02

Mike

1,158
5
22
32

answered Nov 06 '09 at 23:34

Sean A.O. Harney

23,901
4
30
30

quick question, if there's something on port 8080 and you grep '80', wont that give a false positive? – Kieren Johnstone Oct 24 '11 at 19:07
2

Fyi this doesn't work on OS-X. (the question was for Linux) Try simoes answer. – B Robster Nov 29 '12 at 01:01
it will give false positif if another application using the same port. – dieend Aug 01 '13 at 09:27

kenorb · Answer 3 · 2016-04-26T09:17:38.360

netstat

In Linux, check via netstat, e.g.

$ sudo netstat -nap | grep memcached
tcp        0      0 127.0.0.1:11211  0.0.0.0:*  LISTEN      5067/memcached

ps

Use ps to filter the processes:

$ ps wuax | grep memcache
497 5067  0.0  1.3 384824 53928 ? Ssl  Apr11   1:28 memcached -d -p 11211 -u memcached -m 64 -c 1024 -P /var/run/memcached/memcached.pid -l 127.0.0.1

The port can be found next to -p, e.g. -p 11211. If port hasn't been specified, default is 11211.

Bash

You can send stats command to the given port and see if the memcached responds, e.g.

exec 3<>/dev/tcp/localhost/11211; printf "stats\nquit\n" >&3; cat <&3

Telnet

Use telnet to connect to the host and run stats (as above), e.g.

$ telnet localhost 11211
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
stats
STAT pid 23669
STAT uptime 433859

^{Then hit Ctrl-] and Ctrl-D to finish.}

score 7 · Answer 4 · edited Sep 04 '14 at 11:30

7

Use the following command

ps -U user | grep -v grep | grep memcached

edited Sep 04 '14 at 11:30

Mike

1,158
5
22
32

answered Sep 04 '14 at 11:00

uri.lazar

329
3
10

score 5 · Answer 5 · answered Feb 28 '19 at 05:27

You can check memcached status

service memcached status

You will see a line like this at the bottom:

       └─1560 /usr/bin/memcached -vv -m 64 -p 11211 -u memcache -l 127.0.0.1 -P /var/run/memcached/memcached.pid

The -p 11211 is what port it's running on.

score 3 · Answer 6 · answered Nov 07 '09 at 19:10

3

If you're asking this question, it sounds like you're running a really old version. If you did this on a recent version, you'd see this:

% ./memcached
failed to listen on TCP port 11211: Address already in use

answered Nov 07 '09 at 19:10

Dustin

89,080
21
111
133

How do I see if memcached is already running on my chosen port?

6 Answers6

netstat

ps

Bash

Telnet