51
votes
Forward local port or socket file to remote socket file
Altough in the time, when the question was asked, it was really impossible,
but it is possible nowadays.
You can to both: UNIX=>TCP and UNIX=>UNIX forwarding.
For example:
ssh \
-R/var/run/mysql....
- 631
34
votes
How to automatically restart a service on failure in Linux
Only answering the service restart part. I came across Monit as well, but on CentOS 7 systemd takes care of all that for you. You just need to add these two lines to the .service file (if they're not ...
- 538
31
votes
What is the difference between Unix sockets and TCP/IP sockets?
What's the difference between Unix socket and TCP/IP socket?
A TCP/IP socket is used for communication across TCP/IP networks. A connected TCP socket is identified by the combination of local IP, ...
- 4,086
18
votes
Accepted
Running a websocket server and a http server on the same server
A terribly written question, but the term I was looking for was reverse proxy.
Basically, just like how nginx can forward different request to several instances of the web app based on the path or ...
- 412
17
votes
How to find other end of unix socket connection?
Actually, ss from iproute2 (replacement for netstat, ifconfig, etc.) can show this information.
Here is an example showing an ssh-agent unix domain socket to which a ssh process has connected:
$ ...
- 4,251
17
votes
Can't start mysql service
Run mysqld --help and check, if it reports any problems with config
Check logs in /var/log/mysql
Try runnig it directly and check errors:
mkdir /var/run/mysqld/
chown mysql: /var/run/mysqld/
mysqld ...
- 2,166
17
votes
Accepted
Expose a Unix socket to the host system from inside from a Docker container
You can communicate the host machine or even two containers using the same socket. In the general case of two containers, you should start the two dockers from the host machine sharing a volume that ...
- 905
16
votes
Create Unix Named Socket from the Command Line
You can use python:
python -c "import socket as s; sock = s.socket(s.AF_UNIX); sock.bind('/tmp/test.sock')"
Also C, see this answer.
- 1,138
14
votes
Create Unix Named Socket from the Command Line
I simply use netcat and stay listening in such a case:
nc -lkU aSocket.sock
you should use netcat-openbsd. netcat-traditional does not have -U switch which is for Unix Domain socket.
- 241
13
votes
linux : netstat listening queue length
Let's look into source code, as it's the best documentation in the world of open source.
net/ipv4/tcp_diag.c:
if (sk->sk_state == TCP_LISTEN) {
r->idiag_rqueue = sk->sk_ack_backlog;
...
- 406
12
votes
Sharing unix socket via docker volume - permission denied
Its now 2015 and I assume the kernel patch the Michael mentions has now made it's way into the stable kernel. I have a working example of 2 docker containers one with php-fpm and the other with nginx ...
- 121
12
votes
Siege: descriptor table full sock.c:119: Too many open files
To solve this problem for myself, I had to adjust the OS "ulimit" setting:
ulimit -a -- Check current setting
ulimit -n 10000 -- Edit setting value
Source: https://bugs.debian.org/cgi-bin/bugreport....
- 221
11
votes
MySQL Daemon Lock issue
Note to future travelers: It depends on your specific configuration but this is very likely an issue with apparmor. If you don't want to disable locking take a look at syslog and see if you're getting ...
- 211
9
votes
How to find other end of unix socket connection?
I wrote a tool which uses MvG's gdb method to reliably get socket peer information, kernel debug symbols not needed.
To get the process connected to a given socket, pass it the inode number:
# ...
- 221
9
votes
Forward local port or socket file to remote socket file
No more socat is needed since ssh 6.7. You can forward unix domain sockets directly like:
ssh -nNT -L $(pwd)/docker.sock:/var/run/docker.sock user@someremote
More info: https://medium.com/@dperny/...
- 335
9
votes
Accepted
Netcat not able to bind a listening socket
For netcat in listen mode you should use -p flag to choose listening port, e.g. nc -vvv -l -p 5349.
the second error: nnetfd reuseport failed : Protocol not available
is related to SO_REUSEPORT ...
- 3,249
8
votes
Accepted
Connect to Milter service unix:/var/run/opendkim/opendkim.sock: No such file or directory
You will need to set the socket file in spool dir of postfix, e.g:
/var/spool/postfix/var/run/opendkim
After changing that, you might see problem about permission, then just change group owner of ...
- 494
7
votes
TIME_WAIT consumes file descriptors?
The file descriptor is used by application to read/write from the socket. Thus if the application call close(), the file descriptor is immediately released.
On the other hand, if the application call ...
- 386
7
votes
How to set up memcached to use unix socket?
added to /etc/default/memcached:
[ ENABLE_MEMCACHED = yes ] && install -d -o memcache -g www-data -m 0770 /var/run/memcached
# or use setfacl and whatever user/group you want
true # because ...
- 71
6
votes
What are the ramifications of setting tcp_tw_recycle/reuse to 1?
I just had this bite me, so perhaps someone might benefit from my pain and suffering.
First, an involved link with lots of info:
http://vincent.bernat.im/en/blog/2014-tcp-time-wait-state-linux.html
...
- 61
6
votes
Accepted
Redirect subdomains to services on different ports of same server
You cannot directly use a DNS name to map a specific port, in this case where you have a single IP for multiple DNS names.
Your best bet would be to setup Apache or NGinx as a Reverse Proxy to map ...
- 13k
5
votes
Unix socket vs TCP/IP host:port
Pros of Unix domain sockets.
Access can be managed through the Unix user permission system either by setting the permissions on the socket itself or by the server reading the usename of the ...
- 4,086
5
votes
Sniff UNIX domain socket
I know this is not answering the main question, but I've ended up here, searching for just sniffing communication on a socket.
I've decided to post for others like me.
Here's how I did it:
$> sudo ...
- 231
5
votes
Apache load balancer for mod_proxy_wstunnel?
According Apache official documentation :
https://httpd.apache.org/docs/2.4/en/mod/mod_proxy_balancer.html
mod_proxy_balancer requires the service of mod_proxy and it provides load balancing for all ...
- 51
5
votes
Accepted
dnsmasq: failed to create listening socket for port 53: Address already in use
You can do this:
netstat -tupln
you will get result like this:
tcp 0 0 :::80 :::* LISTEN 713/httpd
take the pid for the process that listening on th port 53 and kill it with this ...
- 401
4
votes
Linux command to wait for a SSH server to be up
Something simple like this does the job, waiting 5 seconds between attempts and discarding STDERR
until ssh <host> 2> /dev/null
do
sleep 5
done
- 41
4
votes
Linux command to wait for a SSH server to be up
This is a 'ping_ssh' script I'm using. It handles timeout cases, fast success, and won't prompt for passwords or be fooled by the port being open but not responding as with 'nc' based solutions. This ...
- 191
4
votes
How to determine number of open sockets? VM Resource Issues
To watch live MySQL opened connections through UNIX socket, run (as root):
watch -n1 'netstat -np | grep -i mysqld'
- 190
4
votes
ERROR 2002 MYSQL socket /tmp/mysql.sock
I know this is an older post, but I spent the last hour or so bouncing back and forth between serverfault, StackOverflow, and DataBase administrators trying to figure out how to solve this issue after ...
- 141
4
votes
Accepted
Using nginx to proxy multiple instances of sockets.io
I was having the exact problem and I found this simple workaround :
Configure your client socket.io from your js/html file to connect from subdirectory (The default socket.io setting will have your ...
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