What are the command to start, restart and stop gearman?
So far I know:
gearadmin --shutdown # stop
gearmand -d # I believe it is to restart. Not sure.
Any idea for managing gearman?
If you want to restart the gearmand, then you should use the shell script gearman-job-server. Type the command as sudo service gearman-job-server restart which STOPs and STARTs the server
---------------------- More Information If you need it -----------------------
I assume you have some small confusion over here. It's all because of Terminologies. The name of the application is Gearman which is a Message-Queue System.
I am answering with the assumption tha you are working with Linux OS.
When you try installing the Gearman, the application that gets installed is gearmand which is a Job-Server/executable file. Something like Apache for example.
Refer the link http://manpages.ubuntu.com/manpages/precise/en/man8/gearmand.8.html for the command reference.
Then what's the gearman? gearman is the Client Program/Application, with which you can talk to the gearmand. With gearman you can run client and worker functions from the command line.
Refer the link http://manpages.ubuntu.com/manpages/precise/en/man1/gearman.1.html for the command reference.
So what's gearadmin? It's the tool which allows you to run Admin commands against your gearmand
Refer the link: http://manpages.ubuntu.com/manpages/precise/en/man1/gearadmin.1.html
Now coming to your questions about the command gearmand. From the shell if you run the command as gearmand, the Job Server starts and gets attached to your Shell Process. For ex: if you run php from shell the php runs and starts waiting for your commands right? Same way. If you want to run Gearmand as a background process, then you should run with the param as -d which makes it run as a daemon
So gearmand -d makes it run as Daemon. Not a restart command.
Hope this helps to answer your question and also to clarify in case if you have any confusion over the naming.
How to STOP Gearman Server
==> gearadmin --shutdown
How to START Gearman Server
==> gearmand -d
The popular answer seems to be a bit old, so if you get Failed to restart gearman-job-server.service: Unit not found. when trying to restart the old way, try just sudo service gearmand restart. That's how it seems to work on a CentOS with latest version of gearman.
For restarting the workers on the same system there seems to be a sudo gearmanw-control restart command avaliable.
Related
I have an issue with later versions of ES, so have to use 7.10.2 currently.
This means that the previous method I used to install ES as a service, i.e. apt-get, doesn't work You can't choose an older version this way: it currently installs 7.16.3.
So I followed the procedure on this page for 7.10: everything worked: I was able to run ES as an app and also as a "daemon". Clearly I could simply put the "daemon" startup line in a script which runs on boot.
But what's the optimum way of turning this "daemon arrangement" into a service which you can control with systemctl, and which starts automatically when the machine boots?
PS I don't want to get involved with Docker. I'm sure that's a useful thing but I'm convinced there is a simpler way of doing it, using available Linux sys tools.
I found a workaround... this doesn't in fact create a service of the "systemd" type which can be controlled by systemctl. There seem to be one or two problems which make this non-trivial.
1) You can't start ES as root! I assume (not sure) that most services are being run by root. Anyway this was something I couldn't find a solution to.
2) I am not sure whether a shell script file called by a service is allowed to end... or should continue endlessly: initially I thought this would be sufficient. This is a shell script (run_es_daemon.sh) which does indeed start up ES (as a daemon process) when run by manually in a terminal. There is no issue to do with the fact that the script ends and you then close the terminal: the daemon process continues to run:
#!/bin/bash
# start ES as a daemon...
cd /home/mike/Elasticsearch/elasticsearch-7.10.2
./bin/elasticsearch -d -p pid
... but it never worked using a xxx.service file in /etc/systemd/system/ (maybe because of 1) above). So I also tried adding these lines under the above ones:
while true
do
echo "bubbles"
sleep 60
done
... didn't work either.
In the end I found a simple workaround solution was to start up the daemon process by using crontab:
#reboot /home/mike/sysadmin/run_es_daemon.sh
... but I'd still like to know how to set it up as a true service, which starts at boot...
I wonder if you can help.
I am running the following versions:
OS: SMP Debian 3.2.81-1 x86_64
uWSGI: uWSGI 2.0.11.2
I installed uWSGI manually, as I want to use a specific version. Using the following commands: -
apt-get install build-essential psmisc python-dev libxml2 libxml2-dev python-setuptools
cd /opt/
wget http://projects.unbit.it/downloads/uwsgi-2.0.11.2.tar.gz
tar -zxvf uwsgi-2.0.11.2.tar.gz
mv uwsgi-2.0.11.2/ uwsgi/
cd uwsgi/
python setup.py install
I am trying to replicate the setup on another server that the project is already working on in a live environment (I am essentially setting up a test server environment).
The original server has uWSGI running on boot. To figure out how this is happening, I used
htops
I've been able to identify that uWSGI is running on the existing server with a set of command line switches. I've managed to track down the script that initialises uWSGI with these switches in the init.d folder.
I copied this script to my test server, and ran it using
service script.sh start
After various troubleshooting, mainly involving permissions on socket folders etc, now when I run this script it starts, and if I run htop I can see uWSGI is running and it has the exact same command switches I need.
I thought simply putting the script in init.d and giving it execute permission
chmod +x script.sh
Would be enough so that it starts when the server is switched on... but this appears to not be the case. Because when I issue
reboot
At the terminal, the terminal reboots but when I go into htops, and check for the uWSGI process it is not running.
If however directly after reboot I issue the following command
service script.sh start
The service starts just fine, and I can once again see it in htops.
Research online lead me to the suggestion that I should try to set the script to run automatically using chkconfig. I installed chkconfig using
apt-get chkconfig
and then ran the following command
chkconfig --list
I noticed that all the runtime levels where set to off for the script I am trying to get to execute on boot.
I ran the following command
chkconfig /etc/init.d/script.sh on
And now when I check the script runtime switches with chkconfig, it shows me the following output for my script:
script.sh 0:off 1:off 2:on 3:on 4:on 5:on 6:off
However when I reboot the uWSGI process is still not starting.
Yet if I simply type
service script.sh start
At the terminal the service runs ok, and uWSGI runs fine.
How can I set the script to run when the server restarts?
Edit:
Further research on the live server that is working fine, has determined that it does not appear to be using systemd to launch uWSGI on startup. I logged into the live server and while there is a
/etc/systemd
folder, it has just one folder in it system and no files. The system folder has the following files in it:
multi-user.target.wants sockets.target.wants syslog.service
So there does not appear to be anything uWSGI related in here.
Also what is making me think this is likely something to do with the
/etc/init.d
folder, is that when I run htop and examine the running services (or daemons) not quite sure of the correct terminology in linux. uWSGI is showing in here as running with a signature of command line switches, and the script I have found in /etc/init.d has this exact uWSGI command and same signature of switches, so I'm fairly convinced this is the part of the system that is starting the uWSGI daemon , I just can't figure out what I need to do , to get it to run apart from copying the same file to /etc/init.d on the new server and giving it execute permission.
The OS of the live server is :
SMP Debian 3.2.73-2+deb7u1 x86_64
and the OS I am running on the new server is
SMP Debian 3.2.81-1 x86_64
So they seem fairly similiar? Although I'm not sure how significant the 8 incremements in the least significant digits in the version number is.
On the new server there is no /etc/systemd folder , and on the live server there is a /etc/systemd as explained above. So it does appear to have been installed seperately to the main OS install (as I have a later version of Debian and it wasn't installed on my system by default) - so perhaps there is something related to systemd that is causing the script to start on the live server, but I'm not too sure.
Jessie
In the recent Debian (Jessie) the initv scripts do not work the way they did. And given your kernel version you are not running a Debian that uses initv scripts. The current Debian uses systemd and scripts in /etc/rc.d are run by compatibility features of systemd (the service command is now a systemd command that tries to behave like the old initv command).
You have two options:
Add a line calling the script from /etc/rc.local:
/etc/rc.d/script.sh
This is a rather dirty fix, since it depends on another compatibility feature of systemd. Also, the location of the script does not matter anymore.
Write a full systemd service for uwsgi (this is what I do, and what is recommended by the uwsgi documentation). You would need to create a file called /etc/systemd/system/uwsgi.service with a content similar to:
[Unit]
Description=uwsgi emperor
After=rsyslog.service
[Service]
PIDFile=/run/uwsgi-emperor.pid
ExecStart=/bin/uwsgi --ini /etc/uwsgi/emperor.ini
ExecReload=/bin/uwsgi --reload /run/uwsgi-emperor.pid
ExecStop=/bin/uwsgi --stop /run/uwsgi-emperor.pid
Restart=always
KillSignal=SIGQUIT
Type=notify
StandardError=syslog
NotifyAccess=all
[Install]
WantedBy=multi-user.target
I use the emperor mode (which is also the mode recommended by uwsgi for use with systemd), although it is possible to hack it to run a single process uwsgi (see further reading below).
You will also need to enable the service to be used by the multi-user.target, which will run at boot. You need to perform this as root:
systemctl enable uwsgi.service
And uwsgi will start with the next boot (it will not start straight away, to make it start you need systemctl start uwsgi.service).
Further reading:
The Arch linux wiki about systemd is very thorough
The Debian wiki on systemd is good, but outdated in some places (notably, it tells you that you need to install it which is not the case in Jessie)
Weezy
You're mixing things up a little there: chkconfig is a script of the RedHat family of OSes. Making it work for Debian was not easy in the past, and I do not believe it is easy to do so now.
Weezy still uses the initv rc.d folders alright, for each runlevel one rc.d folder:
/etc/rc.d/rc0.d/
/etc/rc.d/rc1.d/
/etc/rc.d/rc2.d/
/etc/rc.d/rc3.d/
/etc/rc.d/rc4.d/
/etc/rc.d/rc5.d/
/etc/rc.d/rc6.d/
You can check the runlevel you are in with the (appropriately named) runlevel command. Then you need to check whether there is a softlink to the script in the correct /etc/rc.d/rc*.d folder. If there is no softlink to the script you need to add it with something of the lines:
ln -s /etc/rc.d/init.d/script.dh /etc/rc.d/rc$(runlevel | cut -d ' ' -f 2).d/script.sh
And that is almost all about how initv scripts work. If you are going into runlevel 2 when the machine boots (I believe that's the default on Debian), what init performs is simply service <script> start for every file in /etc/rc.d/rc2.d.
I created a cronjob with sudo crontab -u USERNAME -e and tried to start my node.js app after each reboot.
It had worked well at another server.
But this time, I installed the Node.js via nvm
Then tried to run the same cronjob lines, but every time after reboot it failed. I tried to figure out all the related folders and tried again to run as different lines. When I check with forever list, server shows that no process is running.
#reboot /home/USERNAME/.npm/forever start -c /home/USERNAME/.nvm/current/bin/node /home/USERNAME/APPNAME/app
#reboot /home/USERNAME/.npm/forever start /home/USERNAME/APPNAME/app
#reboot /usr/local/bin/forever start -c /home/USERNAME/.nvm/current/bin/node /home/USERNAME/APPNAME/app
I think that the reason is somehow related with nvm. But I am not sure of that. I don't want to do anything unnecessary unless I am fully sure about it.
Edited July 26, 2015
Though I have used the npm's forever module to deploy nodejs production apps, I really do not see the need to use it on linux based servers as there are so many system level alternatives available.
One of them is upstart. It will help you run your scripts as system level services. Amazon Web Services also use upstart in their Elastic Beanstalk nodejs tiers to keep nodejs apps running forever.
If you really just need to get down to it, here is a link to run your nodejs app as an upstart service.
However, it is not limited to deploying nodejs apps only and if you learn upstart, you will be able to do a lot of things with it. Here is a link for that as well.
If your original approach was preferable (as it was in my case) you can fix your scheduled cron job by explicitly passing the path to node like this: (found in this answer)
#reboot /root/.nvm/versions/node/v7.1.0/bin/node /root/.nvm/versions/node/v7.1.0/bin/forever start /var/www/server.json
Apparently NVM works in magic by setting up some system paths which aren't setup at the moment the cron jobs run.
I am trying to start GUI application with upstart script on CentOS. I have test script located /etc/init/ folder.
start on desktop-session-start
stop on desktop-shutdown
respawn
script
export DISPLAY=:0
sleep 5
exec /.1/Projects/UpstartTest/start.sh &
end script
start.sh scripts is running binary files for GUI application.
After reboot my computer. When I typed:
[root#mg-CentOS ~]# initctl status test
test stop/waiting
So my upstart is not runnig. When i type
initctl start test
manually it works fine without any problem.
How can I run this upstart script after user login (desktop started) ? I am trying to find detailed documents for CentOS for upstart but there is no.
For this purpose, you can use the update-rc tool, which is builtin on linux distributions. It basically creates a symbolic link for the script you want to be executed at startup, or some other OS states, on the folder rc.X, where X is the number of the folder that determines a state that you want.
You may want to have a look at this answer: Update-rc.d custom script running too late, and also runs at shutdown
More information about can be found here:
http://www.linux.com/news/enterprise/systems-management/8116-an-introduction-to-services-runlevels-and-rcd-scripts
Detailed information about the CentOS booting process can be found here: https://www.centos.org/docs/5/html/Installation_Guide-en-US/s1-boot-init-shutdown-process.html;
the rc is being explained at this document as well.
I wrote a simple JAVA application which runs as a service. When my application is up and running, I maintain the PID in a file which will be used while stopping the application.
Issue:
When I restart the OS the stop script is not called (not sure how to make this happen) and the old PID is left as it is in the PID file. Now, after reboot (which start my app) when I stop the app using stop script now my stop script will try to clean up all the PID listed in the file. Most of the time, I will get "No such process". But there are chance the same PID might have been used for some other process
Question:
How I can make sure my stop script will be invoked when I shutdown ore reboot the OS? I am looking a solution for RHEL environment.
I think your are looking for a init script. (startup/shutdown services at different run levels)
This is a good reference
http://blog.rimuhosting.com/2009/09/30/one-java-init-script/
this has a good refernce to Linux init.d scripts
http://coreymaynard.com/blog/creating-a-custom-initd-script-on-fedora/
Hope it helps
If you are looking for scripts that run after reboot, I guess you can write the script in /etc/rc.local and then you can start your service.
This script will run after all your init scripts have run while your machine starts. Using this you can delete the old PID file.