One of our application servers (Glassfish v3.0.1) keeps crushing down with no reason. Sometimes, I am away from Internet so I cannot run it back again. Therefore, I wrote a simple bash script to wait for 10 minutes and then run asadmin. It is like:
#!/bin/bash
while true;
do sleep 600;
sudo /home/ismetb/glassfishv3.0.1/glassfish/bin/asadmin start-domain;
done
This seems to work fine however I have a couple of problems:
If I terminate the bash script (by pressing ctrl+z buttons), the Java process (Glassfish) dies and start-domain and stop-domain commands do not work at all. That means, I can neither stop Glassfish nor can I access it. I do not know if anybody else experienced this problem before or not. If the process dies, only thing I can do is to look for the ID of Java process and kill it from terminal. This not desirable at all. Any ideas why Java process dies when I quit script?
What I want to add to my script is something like to check the port Glassfish is using. If port is occupied maybe I can assume that Glassfish is not down! (However, the port (8080 default) might still be used by Glassfish although Glassfish is dead, I am not sure of it). If not, then with the help of a simple code, I can get the id of the Java process and kill them all. Then start-domain command will successfully work. Any ideas or any directions on how I can do this?
You can use a cron job instead. To install a cron job for root, enter
sudo crontab -e
and add this line
*/10 * * * * /home/ismetb/glassfishv3.0.1/glassfish/bin/asadmin start-domain
This will run asadmin every ten minutes.
If you're not comfortable with the command line, you might also try gnome-schedule, but I have no experience with that.
For your second problem, you can use curl or wget to access glassfish. You can try to get some URL, or even access the administration interface, and if you don't get a response, assume glassfish is down.
Related
I'm fairly new to Bash, redis and linux in general and I'm having trouble with creating a script. This is also my first question, I hope it is not a duplicate.
So here's the problem, I'm creating a simple application in ruby for educational purposes, but the feature I'm trying to implement uses redis and sidekiq. What I want to do is to create an executable script (I named it server) that initiates the redis server, initiates the redis, but it should also shutdown redis after the user finalizes the sidekiq.
This is what I came up with:
#!/usr/bin/env sh
set -e
redis-server --daemonize yes
bundle exec sidekiq -r ./a/sample/path/worker.rb
redis-cli shutdown # this is not working, I want to execute this after shutting sidekiq down...
When I run the fourth line, it starts the little Sidekiq "welcome page" and I can't to anything until I shut it down with Control + C. I assumed that after shutting it with this command, it would continue with the script I wrote, which would be the redis-cli shutdown command.
But it does not. When I Control + C the sidekiq, it simply goes back to the command line.
Is there anyone familiar with these concepts that could help me? I wanted a script that would also shutdown redis after I'm done with sidekiq.
Thanks!
Have you considered using Foreman?
http://blog.daviddollar.org/2011/05/06/introducing-foreman.html
https://github.com/ddollar/foreman
I've written a TCP Server in ruby running on port 2000 with event machine.
Right now, what I do is ssh to my server and run the command ruby lib/tcp_server.rb to turn on the server, but it shuts down when I log out.
I've tried nohup and using & but nothing seems to stick for the server for a long time.
So my question is, how do I deploy this server on port 2000 and keep it running, like how we deploy Rails to nginx.
It's not a webserver, but an a tcp server for a connected device, if that helps.
Thanks!
Solution 1: tmux or screen
This is the simplest way to approach, you will have to create a tmux or screen session, then start your server in that session.
Solution 2: nohup
nohup ruby lib/tcp_server.rb > stdout.log 2> stderr.log &
You've tried nohup and using &, I suppose you've already known how to do.
Solution 3: daemonize
You can detach from the shell and daemonize the process by forking
it twice, setting the session ID and changing the current working directory.
def daemonize
exit if fork
Process.setsid
exit if fork
Dir.chdir '/'
end
With this approach, you will have to redirect stdout and stderr to keep logs.
Another way to daemonize is to use gems like daemons.
update:
To restart the process automatically after being killed, you need a process manager like god or pm2.
To start the process automatically after booting, you need to compose an init scripts but how it looks like depends on your service management system and operating system. One of the most well-known is System V. If you are using Ubuntu, you might want to take a look at Upstart or systemd.
I connected via ssh to remoute server and started very long wget downloading. Then ssh session was broke, and after reconnect new copy of interpretator was created. Now I see wget process in ps, but is it possible to return control to old interpretator? I know that better solution is to use screen for long commands, but is there other way?
No, there is no way to reattach a process to a different terminal if it's not set up to do that (by way of screen / tmux / what have you) in the first place.
As a crude approximation, connecting a debugger to the running process may allow you to interact with it in some limited ways, but in this particular scenario, I don't think it will be beneficial.
If you want to know the progress of your currently running wget, check out the size of the downloaded file, it should be growing. If it doesn't, run killall wget and start over.
Next time, consider running wget --background to prevent the problem from happening. See the wget info page.
This command let Wget to work in the background, and write its progress to log file my.log.
Еhe number of retries 45 (-t options)
wget -t 45 -o my.log http://upload.wikimedia.org/wikipedia/commons/5/51/Google.png &
I have a bash script that tests whether the sftp connection exists, very simple one:
$ if [ -d ~/.gvfs/sftp for username on 192.168.1.101 ]; then echo "sftp missing" exit; fi
Now heres the question:
How do I make the script reestablish the previously connected sftp that still has a cached pass to reconnect without having it depend on if the bash script is on?
Since I have a bookmarked sftp thing in nautilus, i just point and click, presto its reconnected. I need the same for my script which will TERMINATE in a couple of lines; in other words the script only reconnects nautilus and dies, connection stays open...
I am still noobish at sftp, besides connecting...
Extra info: I use Ubuntu for both client and server, and i dont mind entering the ssh pass again if its new conection, any help is appreciated :D
Its critical that sftp wont d/c, or die, when i close script, or it ends, nohup cant be used for script since it will be run >10 times per day
Thanks!
Okay, some research done. You are using the GVFS (GNOME Virtual File System), and are looking with a none-GNOME application (bash) on the FUSE mount point of one of the URIs.
I think you can use the gvfs-mount command to reconnect, if you know the SFTP URL, but I didn't really find much documentation about this.
I have a master-workers architecture where the number of workers is growing on a weekly basis. I can no longer be expected to ssh or remote console into each machine to kill the worker, do a source control sync, and restart. I would like to be able to have the master place a message out on the network that tells each machine to sync and restart.
That's where I hit a roadblock. If I were using any sane platform, I could just do:
exec('ruby', __FILE__)
...and be done. However, I did the following test:
p Process.pid
sleep 1
exec('ruby', __FILE__)
...and on Windows, I get one ruby instance for each call to exec. None of them die until I hit ^C on the window in question. On every platform I tried this on, it is executing the new version of the file each time, which I have verified this by making simple edits to the test script while the test marched along.
The reason I'm printing the pid is to double-check the behavior I'm seeing. On windows, I am getting a different pid with each execution - which I would expect, considering that I am seeing a new process in the task manager for each run. The mac is behaving correctly: the pid is the same for every system call and I have verified with dtrace that each run is trigging a call to the execve syscall.
So, in short, is there a way to get a windows ruby script to restart its execution so it will be running any code - including itself - that has changed during its execution? Please note that this is not a rails application, though it does use activerecord.
After trying a number of solutions (including the one submitted by Byron Whitlock, which ultimately put me onto the path to a satisfactory end) I settled upon:
IO.popen("start cmd /C ruby.exe #{$0} #{ARGV.join(' ')}")
sleep 5
I found that if I didn't sleep at all after the popen, and just exited, the spawn would frequently (>50% of the time) fail. This is not cross-platform obviously, so in order to have the same behavior on the mac:
IO.popen("xterm -e \"ruby blah blah blah\"&")
The classic way to restart a program is to write another one that does it for you. so you spawn a process to restart.exe <args>, then die or exit; restart.exe waits until the calling script is no longer running, then starts the script again.