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Before I could use terminal to start Apache service as:
sudo apachectl start
But recently it doesn't work, even after I restart my PC. Instead, I can use XAMPP to start Apache easily. Who can tell me why the terminal doesn't work at all?
Besides, since I'm a beginner with command line, I know the statement
ps aux | grep httpd
can show if apache is running. But I don't know the exact meaning of each field, like:
yy 1708 0.0 0.0 2432772 604 s000 R+ 8:05PM 0:00.00 grep httpd
what does those numbers or characters mean? Is anyone can help? Thanks!
Try sudo apachectl configtest to check that nothing prevents Apache from starting like a syntax error in one of its config files.
If it can't start, then it must throw an error in its log, check in var/log/, ususally there's a apache2 or httpd folder there, containing error and access logs.
The numbers of the ps aux command are explained at the top of each column when you run this command without any grep pipe (which strips the header, because nothing matches httpd in the first line).
More info here: https://www.wikiwand.com/en/Ps_(Unix).
In your case, httpd is not obviously not running since you only get your own ps command as a result so the numbers don't really matter ;-)
I started redis server on ubuntu by typing this on terminal: $redis-server
This results in following > http://paste.ubuntu.com/12688632/
aruns ~ $ redis-server
27851:C 05 Oct 15:16:17.955 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
27851:M 05 Oct 15:16:17.957 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
27851:M 05 Oct 15:16:17.957 # Server can't set maximum open files to 10032 because of OS error: Operation not permitted.
27851:M 05 Oct 15:16:17.958 # Current maximum open files is 4096. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
27851:M 05 Oct 15:16:17.958 # Creating Server TCP listening socket *:6379: bind: Address already in use
How can I fix this problem, it there any manual or automated process to fix this binding.
$ ps aux | grep redis
Find the port that its running on.. In my case..
MyUser 8821 0.0 0.0 2459704 596 ?? S 4:54PM 0:03.40 redis-server *:6379
And then close the port manually
$ kill -9 8821
Re-run redis
$ redis-server
sudo service redis-server stop
I solved this problem on Mac by just typing redis-cli shutdown, after this just
re open the terminal and type redis-server and it will work .
for me, after lots of problems, this solved my issue:
root#2c2379a99b47:/home/ ps -aux | grep redis
redis 3044 0.0 0.0 37000 8780 ? Ssl 14:59 0:00 /usr/bin/redis-server *:6379
after finding redis, kill it!
root#2c2379a99b47:/home# sudo kill -9 3044
root#2c2379a99b47:/homek# sudo service redis-server restart
Stopping redis-server: redis-server.
Starting redis-server: redis-server.
root#2c2379a99b47:/home# sudo service redis-server status
redis-server is running
So as it says, the process is already running so the best to do is to stop it, analyse and restart it and todo so here are the following commands :
redis-cli ping #should return 'PONG'
And this solved my issue:
$ ps -ef |grep redis
root 6622 4836 0 11:07 pts/0 00:00:00 grep redis
redis 6632 1 0 Jun23 ? 04:21:50 /usr/bin/redis-server *:6379
Locate redis process, and stop it!
$ kill -9 6632
$ service redis restart
Stopping redis-server: [ OK ]
Starting redis-server: [ OK ]
$ service redis status
Otherwise if all this doesn't work just try to type redis-cli
Hope it helps :)
This works for me:
$ killall redis-server
And combining everything in one line:
$ killall redis-server; redis-server
I read the documentation on http://www.redis.io , I opened the redis.conf file to configure the redis-server, its located at /etc/redis/redis.conf
$ sudo subl /etc/redis/redis.conf
Instead of sublime editor you can use editor of your choice, viz. nano, vi, emacs, vim, gedit.
In this file I uncommented the #bind 127.0.0.1 line. Hence, instead of 0.0.0.0:6379 now its 127.0.0.1:6379
Restart the redis server
$ sudo service redis-server restart
It will state, The server is now ready to accept connections on port 6379
This will put your server up, For any more detailed configuration and settings you can follow this redis-server on ubuntu
I prefer to use the command param -ef,
ps -ef|grep redis
the -efmeans
-A Display information about other users' processes, including those
without controlling terminals.
-e Identical to -A.
-f Display the uid, pid, parent pid, recent CPU usage, process start
time, controlling tty, elapsed CPU usage, and the associated com-
mand. If the -u option is also used, display the user name
rather then the numeric uid. When -o or -O is used to add to the
display following -f, the command field is not truncated as se-
verely as it is in other formats.
then kill the pid
kill -9 $pid
You may try
$ make
then
$ sudo cp src/redis-cli /usr/local/bin/ on terminal to install the redis and it's redis-cli command.
finally, you can use the redis-cli shutdown command. Hope this answer could help you.
Killing the process that was running after booting in the OS worked for me. To prevent redis from starting at startup in Ubuntu OS:
sudo systemctl disable redis-server
In my case, I tried several times to kill the port manually and didn't work. So I took the easy path, reinstallation and worked like charm after that. If you're in Debian/Ubuntu:
sudo apt remove redis-server // No purge needed
sudo apt update
sudo apt install redis-server // Install once again
sudo systemctl status redis-server // Check status of the service
redis-server // initializes redis
Not the most technical-wise path, but nothing else worked.
It may also happen if you installed Redis via snap and are trying to run it from somewhere else.
If this is the case, you can stop the service via sudo snap stop redis.
I'm not sure, but when I first time installed redis and faced this message, turned out that's due to the redis-server first of all takes configure parameters or path/to/redis.conf, so when I passed nothing after "redis-server" it was trying to execute default redis.conf (bind 127.0.0.1, port 6379 ...) thereby overwrite the existing default redis.conf (which contains same "bind" and "port"!!). That's why I've seen this error, but it's possibly you have another reasons
The problem shows that the default port that redis uses 6379is already in use by some other process.
So simply change the port of redis server
redis-server --port 7000 will start a Redis server using port number 7000.
and then
redis-cli -p 7000 - Now use this to make your client listen at this port.
The Redis startup script is supposed to create a pid file at startup, but I've confirmed all the settings I can find, and no pid file is ever created.
I installed redis by:
$ yum install redis
$ chkconfig redis on
$ service redis start
In my config file (/etc/redis.conf) I checked to make sure these were enabled:
daemonize yes
pidfile /var/run/redis/redis.pid
And in the startup script (/etc/init.d/redis) there is:
exec="/usr/sbin/$name"
pidfile="/var/run/redis/redis.pid"
REDIS_CONFIG="/etc/redis.conf"
[ -e /etc/sysconfig/redis ] && . /etc/sysconfig/redis
lockfile=/var/lock/subsys/redis
start() {
[ -f $REDIS_CONFIG ] || exit 6
[ -x $exec ] || exit 5
echo -n $"Starting $name: "
daemon --user ${REDIS_USER-redis} "$exec $REDIS_CONFIG"
retval=$?
echo
[ $retval -eq 0 ] && touch $lockfile
return $retval
}
stop() {
echo -n $"Stopping $name: "
killproc -p $pidfile $name
retval=$?
echo
[ $retval -eq 0 ] && rm -f $lockfile
return $retval
}
These are the settings that came by default with the install. Any idea why no pid file is created? I need to use it for Monit.
(The system is RHEL 6.4 btw)
For those experiencing on Debian buster:
Editing
nano /etc/systemd/system/redis.service
and adding this line below redis [Service]
ExecStartPost=/bin/sh -c "echo $MAINPID > /var/run/redis/redis.pid"
It suppose to look like this:
[Service]
Type=forking
ExecStart=/usr/bin/redis-server /etc/redis/redis.conf
ExecStop=/bin/kill -s TERM $MAINPID
ExecStartPost=/bin/sh -c "echo $MAINPID > /var/run/redis/redis.pid"
PIDFile=/run/redis/redis-server.pid
then:
sudo systemctl daemon-reload
sudo systemctl restart redis.service
Check redis.service status:
sudo systemctl status redis.service
The pid file now should appear.
On my Ubuntu 18.04, I was getting the same error.
Error reported by redis (on /var/log/redis/redis-server.log):
# Creating Server TCP listening socket ::1:6379: bind: Cannot assign requested address
This is because I've disabled IPv6 on this host and redis-server package (version 5:4.0.9-1) for Ubuntu comes with:
bind 127.0.0.1 ::1
Editing /etc/redis/redis.conf and removing the ::1 address solves the problem. Example:
bind 127.0.0.1
Edit: As pointed out in the comments (thanks to #nicholas-vasilaki and #tommyalvarez), by default redis only allows connections from localhost. Commenting all the line, using:
# bind 127.0.0.1 ::1
works, but makes redis listen from the network (not only from localhost).
More details can be found in redis configuration file.
Problem was that the user redis did not have permission to create the pid file (or directory it was in). Fix:
sudo mkdir /var/run/redis
sudo chown redis /var/run/redis
Then I killed and restarted redis and sure enough, there was redis.pid
In CentOs 7 i need to add to the file:
$ vi /usr/lib/systemd/system/redis.service
The next line:
ExecStartPost=/bin/sh -c "echo $MAINPID > /var/run/redis/redis.pid"
And then restart the service:
$ sudo systemctl daemon-reload
$ sudo systemctl restart redis.service
Reference:
CentOs 7: Systemd & PID File
i had a similar problem on Debian Buster, systemd complains about the missing PID file, even though the file exists and redis is running.
on my system the solution using "echo $MAINPID > /run/redis/redis.pid" works by accident, although/because the real PID file is set to /run/redis/redis-server.pid (spot the different filenames!) and on my system the content of /run/redis/redis.pid (the one of the echo) was empty.
in a discussion on systemd-devel#lists.freedesktop.org someone writes:
... systemd will add the MAINPID environment variable any time it
knows what the main PID is. It learns this by reading the PID file ...
So by the time ExecStartPost runs, the main PID may or may not be
known.
having an empty MAINPID environment variable can be even harmful: if you notice the different PID filenames in the suggested solution, and correct it, you may end up in a situation where the PID file written by redis gets overwritten by an empty file. this happened to me, the result was that systemctl start redis.service never finished.
i also noticed that another server with 100% same OS and configuration, but different hardware did not have this problem.
my conclusion is that it just hits some sort of race condition, systemd seems to look for a PID file just a little too early. on my system, whatever command i used as ExecStartPost, it will add enough delay to make the error disappear.
therefore a solution is to use "sleep 1" (sleep 0.1 works too, but 1 second may be on the safe side):
ExecStartPost=/bin/sleep 1
/etc/systemd/system/redis.service now looks like:
[Service]
Type=forking
ExecStart=/usr/bin/redis-server /etc/redis/redis.conf
ExecStartPost=/bin/sleep 1
ExecStop=/bin/kill -s TERM $MAINPID
PIDFile=/run/redis/redis-server.pid
...
an alternative solution is to use "supervised systemd":
/etc/redis/redis.conf:
# If you run Redis from upstart or systemd, Redis can interact with your
# supervision tree. Options:
# supervised no - no supervision interaction
# supervised upstart - signal upstart by putting Redis into SIGSTOP mode
# supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
# supervised auto - detect upstart or systemd method based on
# UPSTART_JOB or NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal "process is ready."
# They do not enable continuous liveness pings back to your supervisor.
supervised systemd
override the redis-server.service file using:
systemctl edit redis-server.service
and enter the following:
[Service]
Type=notify
reload the service and the error should be gone:
sudo systemctl restart redis.service
sudo systemctl status redis.service
Here from 2018
Before start, I am on Ubuntu 18.04.I wrote this if anyone comes here
by searching same error.
In my case error is the same but problem is so different. No solutions that proposed here worked.
So I checked logs if they are exist and looked for is there anything useful. Found them on;
cat /var/log/redis/redis-server.log
Searched logs and found that problem is that another service is listening same port.
2963:C 21 Sep 11:07:33.007 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
2963:C 21 Sep 11:07:33.008 # Redis version=4.0.9, bits=64, commit=00000000, modified=0, pid=2963, just started
2963:C 21 Sep 11:07:33.008 # Configuration loaded
2974:M 21 Sep 11:07:33.009 # Creating Server TCP listening socket 127.0.0.1:6379: bind: Address already in use
I checked who is listening.
netstat anp | grep 6379
Found it.
tcp6 0 0 :::6379 :::* LISTEN 3036/docker-proxy
It was docker image of redis that installed by another tool
root#yavuz:~# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a6a94d401700 redis:3.2 "docker-entrypoint.s…" 20 hours ago Up 3 hours 0.0.0.0:6379->6379/tcp incubatorsuperset_redis_1
So I stopped docker image
root#yavuz:~# docker stop incubatorsuperset_redis_1
And redis-server started without problem.
root#yavuz:~# systemctl start redis-server
root#yavuz:~# systemctl status redis-server
● redis-server.service - Advanced key-value store
Active: active (running) since Fri 2018-09-21 11:10:34 +03; 1min 49s ago
Process: 3671 ExecStart=/usr/bin/redis-server /etc/redis/redis.conf (code=exited, status=0/SUCCESS)
For CentOS:
In my case name of Redis server is redis.service, start it edit
systemctl edit redis.service
Add this:
[Service]
ExecStartPost=/bin/sh -c "echo $MAINPID > /var/run/redis/redis.pid"
PIDFile=/var/run/redis/redis.pid
Im my case it create file: /etc/systemd/system/redis.service.d/override.conf
After restart service:
systemctl daemon-reload
systemctl restart redis
And the pid file is:
cat /var/run/redis/redis.pid
=> 19755
sudo nano /etc/redis/redis.conf
Inside the file, find the supervised directive. This directive allows you to declare an init system to manage Redis as a service, providing you with more control over its operation. The supervised directive is set to no by default. Since you are running Ubuntu, which uses the systemd init system, change this to systemd.
My default, Redis does not run as a daemon, and that is why it does not create a pid file. If you look at /etc/redis/redis.conf, it says so explicitly under General.
#By default Redis does not run as a daemon. Use 'yes' if you need it...
daemonize no
So all you need to do is to change it to daemonize yes
For people struggling with getting it to work on Ubuntu 18.04 you need to edit /etc/redis/redis.conf and update the pidfile declaration to following:
pidfile "/var/run/redis/redis-server.pid"
Ubuntu 18. /var/run/redis had the wrong permissions:
drwxr-sr-x 2 redis redis 60 Apr 27 12:22 redis
Changed to 755 (drwxrwxr-x) and the pid file now appears.
In my Rails Project, I am trying to run two different servers at different port. But it fails by giving this error at console.
C:\Rails>rails s
=> Booting Mongrel
=> Rails 3.1.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
A server is already running. Check C:/Rails/tmp/pids/server.pid.Exiting
Please check the updated answer.
After googling a lot, I just delete that file and restart the server. Then again system create that file, then again I delete that file. Now Server is running fine. And System generates another copy at the same place. But it is running well.
DELETE THAT FILE ....
If you want to run two servers then it may again create trouble. So
Both commands are checking the default PID file location (tmp/pids/server.pid), so you're seeing this error. Try running multiple servers like so:
Server 1: bundle exec rails s
Server 2: bundle exec rails s -p 3001 -P tmp/pids/server2.pid
Credit: https://stackoverflow.com/a/14446920/1376448
Thanks
UPDATE after Connor Leech comment about Forman Gem
Foreman can help manage multiple processes that your Rails app depends
upon when running in development. It also provides an export command
to move them into production.
You can use netstat to know which process is holding the rails webserver, then you can kill the pid and start it over again, assuming that for some weird reason the server is not responding or running in background and you don't find another way to restart it..
netstat -plntu | grep 3000
tcp 0 0 0.0.0.0:3000 0.0.0.0:* LISTEN 7656/ruby
The last column shows the PID and the process name, then you only need to do:
kill -9 7656
and rails s to get it working again...
Hope it's useful
I find myself coming back to this webpage a lot to find the lsof -wni tcp:3000 command so I've found this method to be easier.
If you get this message:
A server is already running. Check /Users/username/project/tmp/pids/server.pid.
Exiting
And if you're running on a unix system (mac or linux) you can run these commands:
$ cat /Users/username/project/tmp/pids/server.pid
# output
71030
# Kill the process
$ kill -9 71030
Then run your server again!
I deleted the file with cd'ing in to the tmp directory then removing the file
rm server.pid
Then I restarted the server and I got this error
Exiting/Users/josephmellin/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/socket.rb:206:in `bind': Address already in use - bind(2) for 0.0.0.0:3000 (Errno::EADDRINUSE)
Then I could use the following command to see which process is running.
sudo lsof -iTCP -sTCP:LISTEN -P | grep :3000
And after I entered my password, I got this resoponse
ruby 2786 josephmellin 12u IPv4 0xfeadd8ae849eaec9 0t0 TCP *:3000 (LISTEN)
And then killed the process with the following command
KILL -9 2786
And then restarted the server (you will have a different number than 2786 - I left it here for demo purposes)
Step 1: remove .pid
C:/Rails/tmp/pids/server.pid.Exiting
# IN linux/unix shell
$ rm -rf <path to file>
Sometime this doesn't solve the problem, then you have to kill the process running by localhost, for such cases, follow STEP 2
STEP 2: List the process for localhost and kill it
# For Linux/Unix shell
$ lsof -wni tcp:3000
# output
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
ruby 5946 rails 11u IPv4 79073 0t0 TCP *:3000 (LISTEN)
ruby 5946 rails 12u IPv4 103786 0t0 TCP 127.0.0.1:3000->127.0.0.1:53612 (ESTABLISHED)
# Kill the running process
$ kill -9 5946
run your server again
rails server
ps aux | grep rails
or
bundle exec rails s -p 3001 -P tmp/pids/server2.pid
Every instance of a RoR server creates a PID file. By default it is
#{Rails.root}/tmp/pids/server.pid
and if that file already exists it will refuse to start a new server.
To run more than one server of the same project on the same machine you should manually specify the PID file name for each instance of the server (I recommend simply appending a hyphen and the port number) using the -P option:
rails s -p 1234 -P tmp/pids/server-1234.pid
I'm told in some cases you may need to supply a full (rather than relative) path, but I don't know what those cases are.
You can see the PID for each proccess(the first column) :
ps vax | grep rails
// OR: ps auxw | grep rails
5236 pts/1 Sl+ 1:46 2 0.2 /usr/bin/ruby1.9.1 script/rails s -p 3001
5298 pts/2 Sl+ 0:12 2 0.7 /usr/bin/ruby1.9.1 script/rails s -p 3003
7356 pts/5 Sl+ 0:09 2 0.9 /usr/bin/ruby1.9.1 script/rails s -p 3002
7846 pts/3 Sl+ 0:19 2 1.7 /usr/bin/ruby1.9.1 script/rails s
Then kill the server:
kill -9 <pid>
To kill all running apps with "rails" in the name:
killall -9 rails
Use rails default commands, for example:
rake tmp:clear
Works for me, and really simple. ;)
single line command, that will take care of it.
kill -9 $(more C:/Rails/tmp/pids/server.pid)
I just had this problem, just deleted server.pid file and server works fine!
Remove that file: C:/Rails/tmp/pids/server.pid
A simpler way in which I found lesser commands . Go to the path which says a server is running in your folder structure . Search for the file. On the file itself shows a number which is the process id that is currently running. Lets say if the number is 'x', then simply type this command into your terminal
kill -9 x
However, note that this works in Ubuntu. Not sure, if it works in other OS as well.
Try to change the number in the pid file to another and save it.
I have installed rabbitmq on ubuntu and trying to start it using rabbitmq-server start, however, I'm getting this error:
Activating RabbitMQ plugins ...
0 plugins activated:
node with name "rabbit" already running on "mybox"
diagnostics:
- nodes and their ports on mybox: [{rabbit,38618},
{rabbitmqprelaunch13346,41776}]
- current node: rabbitmqprelaunch13346#mybox
- current node home dir: /var/lib/rabbitmq
- current node cookie hash: 8QRKGluOJOcZ4AAkEdFwQg==
so I try to stop it or restart it using service rabbitmq-server restart but I get the following error: Restarting rabbitmq-server: RabbitMQ is not running
The server's host name hostname -s is mybox.
How do I stop the currently running instance, or at least, how do I manage it? I have no access to it and yet I'm not able to run rabbitmq properly.
Thank you.
Rabbitmq is set to start automatically after it's installed.
I don't think it is configured run with the service command.
To see the status of rabbitmq
sudo rabbitmqctl status
To stop the rabbitmq
sudo rabbitmqctl stop
(Try the status command again to see that it's stopped).
To start it again, the recommended method is
sudo invoke-rc.d rabbitmq-server start
These all work with the vanilla ubuntu install using apt-get
Still not working?
If you've tried unsuccessfully to start or restart rabbitmq, check to see how many processes are running.
ps -ef | grep rabbit
There should be 5 processes running as the user rabbitmq.
If you have more, particularly if they're running as other users (such as root, or your own user) you should stop these processes.
The cleanest way is probably to reboot your machine.
rabbitmq-server refuses to start if the hostname -s value has changed.
The solution suggested here is only for test/development environments.
I had to delete the database to fix it locally.
i.e empty folder /var/lib/rabbitmq (ubuntu) or /usr/local/var/lib/rabbitmq/(mac)
I had similar problem but these suggestions didn't work for me(restart too). When I run rabbitmq-server command, I get a response like that:
$/ rabbitmq-server
BOOT FAILED
===========
Error description:
{error,{cannot_log_to_file,"/var/log/rabbitmq/rabbit#haber01.log",
{error,eacces}}}
....
When I checked permissions of /var/log/rabbitmq/rabbit#haber01.log file, I saw that group has not write permisson for that file. So I gave permission to group with that command:
/var/log/rabbigmq/$ chmod g+w *
then problem has gone!
Maybe this answer help someone.
Seems like the Mnesia database was corrupted. Had to delete it to get sudo service rabbitmq-server start going again !
$ sudo rm -rf /var/lib/rabbitmq/mnesia/
Also make sure that any stray rabbit processes are killed before clearing out
$ ps auxww | grep rabbit | awk '{print $2}' | sudo xargs kill -9
And then
$ sudo service rabbitmq-server start
If you use celery, your queues could reach max size and rabbit won't start because of that. Maybe you wouldn't even able to use rabbitmqctl, so if you can afford to clean the queues, just remove
/var/lib/rabbitmq/mnesia/rabbit#<host>/queues
on unix (look for mnesia DB path on your system).
Be careful: this will remove everything you have in rabbit, so this is a last solution ever.
Have a look what is in the log of the node that you are trying to start. It will be in /var/log/rabbitmq/
It was selinux in my case, rabbit could not bind to its ports.
My brew version of rabbitmq refused to start (after working fine for years without modification by me) too.
$ cat /usr/local/etc/rabbitmq/rabbitmq-env.conf
CONFIG_FILE=/usr/local/etc/rabbitmq/rabbitmq
NODE_IP_ADDRESS=127.0.0.1
NODENAME=rabbit#localhost
RABBITMQ_LOG_BASE=/usr/local/var/log/rabbitmq
I edited out rabbit# on NODENAME and brew services restart rabbitmq started working again.
If the standard stop and start are not working, list the rabbitmq processes that are running using
ps aux | grep rabbitmq
Kill the beam.smp process using
kill -9 {process id}
and start the rabbitmq-server again.