Why is my script to start UWSGI not functioning at bootup? - linux

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.

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Is this command properly starting the server? How can I tell?
Since the "proper" command was not functioning as I thought it should, I used the command sudo systemctl *start* corenlp.service and checked the service's status with sudo systemctl *status* corenlp.service. I am not sure if this is an appropriate way in which to start and stop a 'Dedicated CoreNLP Server' but I can control the service. I just do not know if I am actually starting and stopping my dedicated server.
Can I use systemctl command to operate my Dedicated CoreNLP Server?
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inittab not restarting service after service crash in Red Hat 6.7

NOTE: I am running Red Hat 6.7
I have a service that is configured with the Linux init system to start a process as a service when the machine boots. This was done by doing this one-time configuration from the command line:
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On RHEL 6.X, at top of the /etc/inittab file it says:
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#
# ADDING OTHER CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM
RHEL 6.X uses Upstart instead of the System V init system. See the man pages for initctl(8) and initctl(5), or ask Google about Upstart.

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I'm pretty new to linux, so please be well explained :)
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