upstart interview questions
Top upstart frequently asked interview questions
I am looking to daemonize my Node.js application. What's the difference between upstart and forever? Also, are there other packages I might want to considering looking at?
Source: (StackOverflow)
First of all I have many Django instances setup and running like this.
In each project I have a script.sh shell script that starts gunicorn etc.:
#!/bin/bash
set -e
LOGFILE=/var/log/gunicorn/app_name.log
LOGDIR=$(dirname $LOGFILE)
NUM_WORKERS=3
# user/group to run as
USER=root
GROUP=root
PORT=8060
IP=127.0.0.1
cd /var/www/webapps/app_name
source ../bin/activate
test -d $LOGDIR || mkdir -p $LOGDIR
exec /var/www/webapps/bin/gunicorn_django -b $IP:$PORT -w $NUM_WORKERS \
--user=$USER --group=$GROUP --log-level=debug --log-file=$LOGFILE 2>>$LOGFILE
When running this script from the command line with bash script.sh, the site works perfectly, so Nginx is setup right.
As soon as I use upstart with service app_name start the app starts and then just stops. It does not even write to the log file.
This is the app_name.conf file in /etc/init/app_name.conf :
description "Test Django instance"
start on runlevel [2345]
stop on runlevel [06]
respawn
respawn limit 10 5
exec /var/www/webapps/app_name/script.sh
So what is the problem here? Cause running from command line works, but doing trough upstart does not. And I dont know where to see whats wrong?
Source: (StackOverflow)
I have a local docker-registry that I'd like to manage with upstart.
I have the following script (in /etc/init/docker-registry.conf):
description "docker registry"
author "me"
start on filesystem and started docker
stop on runlevel [!2345]
respawn
script
/usr/bin/docker.io run -a stdout --rm --name=docker-registry \
-v /var/local/docker-registry:/var/local/docker-registry \
-p 5000:5000 mysite:5000/docker-registry
end script
I can start my docker registry fine with:
sudo start docker-registry
Response: docker-registry start/running, process 8620
Check to confirm its running?
sudo status docker-registry
Response: docker-registry start/running, process 8620
Trying to stop it with:
sudo stop docker-registry
Response: docker-registry stop/waiting
However, it doesn't actually stop. The process is still alive, the container is running, and it's still functioning perfectly
It does stop perfectly with:
docker stop docker-registry
I've tried adding this to the upstart script:
post-stop script
docker stop docker-registry
end script
But it just returns:
stop: Job failed while stopping
Source: (StackOverflow)
This is on an Ubuntu 12.04.3 LTS server.
I've added the following to /etc/security/limits.conf (my Golang processes run as root):
* hard nofile 50000
* soft nofile 50000
root hard nofile 50000
root soft nofile 50000
I've added the following to /etc/pam.d/common-session
session required pam_limits.so
I've added the following to /etc/sysctl.conf:
fs.file-max = 50000
Yet when I cat /proc/{PID}/limits, I get:
Limit Soft Limit Hard Limit Units
Max open files 1024 4096 files
This happens only when I start the process from Upstart via sudo initctl start service_name. If I start the process myself, it acknowledges my settings.
How do I fix this?
Source: (StackOverflow)
I have written a logging application in Python that is meant to start at boot, but I've been unable to start the app with Ubuntu's Upstart init daemon. When run from the terminal with sudo /usr/local/greeenlog/main.pyw, the application works perfectly. Here is what I've tried for the Upstart job:
/etc/init/greeenlog.conf
# greeenlog
description "I log stuff."
start on startup
stop on shutdown
script
exec /usr/local/greeenlog/main.pyw
end script
My application starts one child thread, in case that is important. I've tried the job with the expect fork stanza without any change in the results. I've also tried this with sudo and without the script statements (just a lone exec statement). In all cases, after boot, running status greeenlog returns greeenlog stop/waiting and running start greeenlog returns:
start: Rejected send message, 1 matched rules; type="method_call", sender=":1.61" (uid=1000 pid=2496 comm="start) interface="com.ubuntu.Upstart0_6.Job" member="Start" error name="(unset)" requested_reply=0 destination="com.ubuntu.Upstart" (uid=0 pid=1 comm="/sbin/init"))
Can anyone see what I'm doing wrong? I appreciate any help you can give. Thanks.
Source: (StackOverflow)
I am trying to do a syntax check on an upstart script using init-checkconf. However when I run it, it returns ERROR: version of /sbin/initctl too old.
I have no idea what to do, I have tried reinstalling upstart but nothing changes. This is being run from within a docker container (ubuntu:14.04) which might have something to do with it.
Source: (StackOverflow)
the standard upstart script that comes with mongodb works fine:
# Ubuntu upstart file at /etc/init/mongodb.conf
limit nofile 20000 20000
kill timeout 300 # wait 300s between SIGTERM and SIGKILL.
pre-start script
mkdir -p /var/lib/mongodb/
mkdir -p /var/log/mongodb/
end script
start on runlevel [2345]
stop on runlevel [06]
script
ENABLE_MONGODB="yes"
if [ -f /etc/default/mongodb ]; then . /etc/default/mongodb; fi
if [ "x$ENABLE_MONGODB" = "xyes" ]; then exec start-stop-daemon --start --quiet --chuid mongodb --exec /usr/bin/mongod -- --config /etc/mongodb.conf; fi
end script
if i want to run a second instance of mongod i thought i just copy both /etc/mongodb.conf -> /etc/mongodb2.conf and /etc/init/mongodb.conf -> /etc/init/mongodb2.conf and change the std port in the first conf-file. then adjust the script above to start with the newly created /etc/mongodb2.conf.
i can then just say start mongodb2and the service starts ... but it is killed right after starting. what do i change, to get both processes up and running?
# Ubuntu upstart file at /etc/init/mongodb2.conf
limit nofile 20000 20000
kill timeout 300 # wait 300s between SIGTERM and SIGKILL.
pre-start script
mkdir -p /var/lib/mongodb2/
mkdir -p /var/log/mongodb2/
end script
start on runlevel [2345]
stop on runlevel [06]
script
ENABLE_MONGODB="yes"
if [ -f /etc/default/mongodb ]; then . /etc/default/mongodb; fi
if [ "x$ENABLE_MONGODB" = "xyes" ]; then exec start-stop-daemon --start --quiet --chuid mongodb --exec /usr/bin/mongod -- --config /etc/mongodb2.conf; fi
end script
Source: (StackOverflow)
I really enjoy using upstart. I currently have upstart jobs to run different gunicorn instances in a number of virtualenvs. However, the 2-3 examples I found for Celery upstart scripts on the interwebs don't work for me.
So, with the following variables, how would I write an Upstart job to run django-celery in a virtualenv.
Path to Django Project:
/srv/projects/django_project
Path to this project's virtualenv:
/srv/environments/django_project
Path to celery settings is the Django project settings file (django-celery):
/srv/projects/django_project/settings.py
Path to the log file for this Celery instance:
/srv/logs/celery.log
For this virtual env, the user:
iamtheuser
and the group:
www-data
I want to run the Celery Daemon with celerybeat, so, the command I want to pass to the django-admin.py (or manage.py) is:
python manage.py celeryd -B
It'll be even better if the script starts after the gunicorn job starts, and stops when the gunicorn job stops. Let's say the file for that is:
/etc/init/gunicorn.conf
Source: (StackOverflow)
I have a websocket service. it's strage that have error:"too many open files", but i have set the system configure:
/etc/security/limits.conf
* soft nofile 65000
* hard nofile 65000
/etc/sysctl.conf
net.ipv4.ip_local_port_range = 1024 65000
ulimit -n
//output 6500
So i think my system configure it's right.
My service is manage by supervisor, it's possible supervisor limits?
check process start by supervisor:
cat /proc/815/limits
Max open files 1024 4096 files
check process manual start:
cat /proc/900/limits
Max open files 65000 65000 files
The reason is used supervisor manage serivce. if i restart supervisor and restart child process, it's "max open files" ok(65000) but wrong(1024) when reboot system supervisor automatically start.
May be supervisor start level is too high and system configure does not work when supervisor start?
edit:
system: ubuntu 12.04 64bit
It's not supervisor problem, all process auto start after system reboot are not use system configure(max open files=1024), but restart it's ok.
update
Maybe the problem is:
Now the question is, how to set a global nofile limit because i don't want to set nofile limit in every upstart script which i need.
Source: (StackOverflow)
I'm having trouble starting an Upstart script.
Here's the script (app.conf in /etc/init/)
description "node.js server"
author "kvz"
start on startup
stop on shutdown
script
# We found $HOME is needed. Without it, we ran into problems
export HOME="/root"
exec sudo -u /usr/local/bin/node \
/var/www/vhosts/travelseguro.com/node/app.js \
2>&1 >> /var/log/node.log
end script
When I run sudo start app, I get:
start: Unknown job: app
How can I make this work?
Source: (StackOverflow)
Starting Node.js with Upstart, when trying to access files within Node.js it cannot access them without using the full path. I need it to use the working directory.
start on startup
stop on shutdown
script
echo $$ > /var/run/mynodeapp.pid
exec sudo -u mynodeapp node server.js >> /var/log/mynodeapp.sys.log 2>&1
end script
pre-start script
echo "Starting" >> /var/log/mynodeapp.sys.log
end script
pre-stop script
rm /var/run/mynodeapp.pid
echo "Stopping" >> /var/log/mynodeapp.sys.log
end script
Source: (StackOverflow)
I am using upstart to start/stop/automatically restart daemons. One of the daemons forks 4 times. The upstart cookbook states that it only supports forking twice. Is there a workaround?
How it fails
If I try to use expect daemon or expect fork, upstart uses the pid of the second fork. When I try to stop the job, nobody responds to upstarts SIGKILL signal and it hangs until you exhaust the pid space and loop back around. It gets worse if you add respawn. Upstart thinks the job died and immediately starts another one.
Bug acknowledged by upstream
A bug has been entered for upstart. The solutions presented are stick with the old sysvinit, rewrite your daemon, or wait for a re-write. RHEL is close to 2 years behind the latest upstart package, so by the time the rewrite is released and we get updated the wait will probably be 4 years. The daemon is written by a subcontractor of a subcontractor of a contractor so it will not be fixed any time soon either.
Source: (StackOverflow)
I am trying to export my application to another process management format/system (specifically, upstart). In doing so, I have come across a number of roadblocks, mostly due to lacking documentation.
As a non-root user, I ran the following command (as shown here):
-bash> foreman export upstart /etc/init
ERROR: Could not create: /etc/init
I "could not create" the directory due to inadequate permissions, so I used sudo:
-bash> sudo foreman export upstart /etc/init
Password:
ERROR: Could not chown /var/log/app to app
I "could not chown... to app" because there is no user named app.
Where is app coming from?
How should I use forman to export to upstart?
Source: (StackOverflow)
I've recently become quite fond of Upstart. Previously I've been using God, Monit and Bluepill but I don't really like these solutions so I'm giving Upstart a try.
I've been using the Foreman gem to generate some basic Upstart configuration files for my processes in /etc/init. However, these generated files only handle the respawning of a crashed process. I was wondering whether it's possible to tell Upstart to restart a process that's consuming for example > 150mb of memory, as you would with Monit, God or Bluepill.
I read through the Upstart docs and this looks like the thing I'm looking for. Though I have no clue how to config something like this.
What I basically want is quite simple. I want to restart my web process if the memory usage is > 150mb ram. These are the files I have:
|-- myapp-web-1.conf
|-- myapp-web-2.conf
|-- myapp-web-3.conf
|-- myapp-web.conf
|-- myapp.conf
And their contents are:
myapp.conf
pre-start script
bash << "EOF"
mkdir -p /var/log/myapp
chown -R deployer /var/log/myapp
EOF
end script
myapp-web.conf
start on starting myapp
stop on stopping myapp
myapp-web-1.conf / myapp-web-2.conf / myapp-web-3.conf
start on starting myapp-web
stop on stopping myapp-web
respawn
exec su - deployer -c 'cd /var/applications/releases/20110607140607; cd myapp && bundle exec unicorn -p $PORT >> /var/log/myapp/web-1.log 2>&1'
Any help much appreciated!
Source: (StackOverflow)
We use PHP gearman workers to run various tasks in parallel. Everything works just fine, and I have silly little shell script to spin them up when I want them. Being a programmer (and therefore lazy), I wanted to see if I could spin these up via an upstart script.
I figured out how to use the instance stanza, so I could start them with an instance number:
description "Async insert workers"
author "Mike Grunder"
env SCRIPT_PATH="/path/to/my/script"
instance $N
script
php $SCRIPT_PATH/worker.php
end script
And this works great, to start them like so:
sudo start async-worker N=1
sudo start async-worker N=2
The way I want to use these workers is to spin up some number of them (maybe one per core, etc), and I would like to do this on startup. To be clear, I don't need the upstart script to detect the number of cores. I'm happy to just say "do 8 instances", but that's why I want multiple running. Is there a way for me to use the "start on" clause in an upstart script to do this automatically?
For example, start instance 1, 2, 3, 4? Then have them exit on shutdown properly?
I suppose I could hook this into an init.d script, but I was wondering if upstart can handle something like this, or if anyone has figured out this issue.
Cheers guys!
Source: (StackOverflow)