Cannot connect to X11 from service - c

I have written a daemon that connects to the X server and queries information periodically. I have configured the daemon to run on startup as a service, using chkconfig. It is set for run level 5. The start command for the init script runs the command my_daemon &.
When the daemon is running, however, it cannot connect to the X server display, even after several minutes. The command I use to connect is:
display = XOpenDisplay(NULL)
The script works fine when I just run my_daemon & manually from a terminal. So, how can I get it working as a startup service?

Related

Does a Lightsail launch script only run at new instance initialisation?

When creating a new Ubuntu Lightsail instance and adding a launch script is the script you enter only run when you FIRST initialize the instance and NOT every time you reboot or restart the same instance? I would love to automate updates and install applications when I create the instance, but I would also like to run updates and start servers when the instance is rebooted or restarted.
Can I (should I) use the launch script for this? Or would it be better to create a second script to do all the tasks after reboot?

How to exit Plink used to forward a port of SQL server connection, when SQL server job is completed

I have setup PuTTY/Plink to connect to a remote server for loading data from the remote SQL server.
I can easily call the saved session by using the following:
c:\plink -l myusername savedsite
I can then run a SQL Server job that loads the data.
The issue I have is, that this SQL Server job is a scheduled job that runs every x minutes.
What I notice is that running the Plink command keeps the command window open. So on the subsequent run of the job, another command window opens.
What I want to do is to issue an exit/logout command to the Plink window when the task of loading the data is complete. How do I achiever this please?
OK, it does not looks like you will provide us enough information, so that we can give you a good answer.
So only briefly: Plink won't close for you. It cannot know when you are done.
You have to close it on your own. E.g. by:
Starting it with a redirected input and writing exit/logout to it; or
Remembering its process ID and killing it.
We cannot show you how, as we do not know anything about the way you run it and options your environment allow.

wildfly-maven-plugin:1.2.1.Final start and run do not work for remote host

I have used wildfly-maven-plugin:1.2.1.Final and deploy,undeploy & shutdown all work for locally and also remotely.
The problem I is that the start and run goals do not work for a remote host. It seems like it does not use the same config for goals like deploy, undeploy & shutdown
Any ideas how I configure so that run or start work for remote host?
Thanks,
daslan
The wildfly-maven-plugin cannot start a remote WildFly instance. With both the start and run goals the plugin starts a new process locally. There is no way, at least that I'm aware of, to start a new process on a remote machine.
The deploy, redeploy, undeploy and shutdown goals work because they send requests over the management API.

is it possible execute a perl script with admin rights or as a specific user?

I'm writing a perl script in which I've to shutdown my mssql server ,do some operation and then I've to restart it.I know 1 way is to use netstat to stopt the service but I cann't use that. So I tried installing DBI and DBD::ODBC module.
More info here :Shutdown MSSQL server from perl script DBI
But when I trying to shutdown my server using this command
$dbh->prepare("SHUTDOWN WITH NOWAIT ");
It's not working for me :
I got this response from the community
SHUTDOWN permissions are assigned to members of the sysadmin and serveradmin fixed server roles, and they are not transferable. I'd consider it unlike(hopefully) that perl is run with this rights.
So please tell me is there a way to run the above command as these users ? or what can I do other than this . Note that I have a constraint tha tI cann't simply stop it as windows service.
If the scripts are executed through a web browser then the user executing the scripts will be defined by the web server. It will probably not be a good idea to fiddle with this user. Just leave things as they are.
What you can do is to create a Perl script that is being run by a privileged user on a consistent basis with CRON.
This script being run by CRON can check for specific content like a file which has been written by a script where the user executing the script has lesser privileges.
So the way it could work is as follows:
You execute browser.cgi through a browser to do a specific task.
browser.cgi writes instructions to a file.
Every 1 minute priveleged.cgi executes via CRON. (The root user could execute priveleged.cgi)
priveleged.cgi reads the file browser.cgi has written for instructions and starts and stops services according to the instructions.

Running batch file remotely using Hudson

What is the simplest way to schedule a batch file to run on a remote machine using Hudson (latest and greatest version)? I was exploring the master slave setup. I created a dumb slave but I am not sure what the parameters should be so that I can trigger the batch file in the remote slave machine.
Basically, I am trying to run 2 different batch files on two different remote machines sequentially, triggered from my machine (the master). The Step by step guide on the Hudson website is a dead link. There are similar questions posted on SO but it does not quite work for me when I use the parameters they mention.
If anyone has done something similar please suggest ways to make this work.
(I know how to set up jobs, and add a step to run a batch file etc what I am having trouble configuring is doing this on a remote machine using hudson in built features)
UPDATE
Thank you all for the suggestions. Quick update on this:
What I wanted to get done is partially working, below are the steps followed to get to it -
Created new Node from Manage Nodes -> New Node -> set # of Executors as 1, Remote FS root set as '/var/hudson', set Launch method as using JNLP, set slavename and saved.
Once slave was set up (from master machine), I logged into the Slave physical machine, I downloaded the _slave.jar from http://masterserver:port/jnlpJars/slave.jar, and ran the following from command line at the download location -> java -jar _slave.jar -jnlpUrl http://masterserver:port/computer/slavename/slave-agent.jnlp. The connection was made successfully.
Checked 'Restrict where this project can be run' in the Master job configuration, and set paramater as slavename.
Checked "Add Build Step" for adding my batch job script
What I am still missing now is a way to connect to 2 slaves from one job in sequence, is that possible?
It is fairly easy and straight forward. Lets assume you already have a slave running. Then you configure the job as if you are locally on the target box. The setting for Restrict where this project can be run needs to be the node that you want to on. This is all for the job configuration.
For the slave configuration read the following pages.
Installing Hudson as a Windows service
Distributed builds
On windows I prefer to run the slave as a service and let the remote machine manage the start up and shut down of the slave. The only disadvantage with this is, you need to upgrade the client every time you update the server Just get the new client.jar from the server, after the upgrade and put it on the slave. Then restart the slave and you are done.
I had troubles using the install as a service option for the slave even though I did it as a local administrator. I used then srvany to wrap the jar into a service. Here is a blog about it. The command that you need to wrap, you will get from your Hudson server from the slave page. For all of this to work, you should set up the slave management as jnlp.
If you have an ssh server on your target machine, you can use the ssl slave settings. These work for me like a charm. I use them with my unix slaves. So far the ssl option with unix is less of an hassle, than the windows service clients.
I had some similar trouble with slave setup and wrote up this blog post - I was running on Linux rather than Windows, but hopefully this will help.
I dont know about how to use built-in hudson features for this job - but in one of my project builds, i run a batch file that in turn uses PSTools
to run the job on a remote server. I found PS tools extremely easy to use - download, unpack and run the command with the right parameters, hence opted to use this.

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