up vote 1 down vote favorite
share [g+] share [fb]

I've recently been moving our instances to EBS instances (CentOS) and still have a bit of confusion on what's happening when I "stop" and instance. I have some of my services with runlevels 345 on but when I start a stopped instance the services don't start. What's actually happening when I issue a stop command to the instance, and how do I get my services to start automatically when I start the instance up again?

link|improve this question
40% accept rate
Rebooting the instance seemed to get everything to work. I'm going to chalk it up as a fluke or some other reason. – tgm Jan 11 '10 at 20:01
feedback

2 Answers

up vote 0 down vote

Do you mean that you're putting the system files for your EC2 instances on persistent EBS volumes, rather than using the instance file system which goes away when you stop or restart the instance ?

If so, when you shut down an instance, the files on your EBS volume will be preserved but the files on the other file systems provided by the instance (these used to be / and /mnt, but I'm not sure what happens with an EBS instance) will disappear.

I'm guessing that your services don't start at boot time because they are dependent on files that aren't stored on the EBS volume. The service logs ought to help you debug the problem.

link|improve this answer
No, I'm using the new EBS backed AMI's (vs S3 backed). So the instances can be stopped (paused) without being terminated. It's my understanding they (EBS instances) work more like a physical server. – tgm Jan 6 '10 at 16:49
Interesting - this made me go and look up how the EBS instances work. If you "stop" an instance it looks like it does shut down the instance, but preserves the EBS volume and the instance ID so that you can restart with the same ID (but not necessarily the same internal IP address, apparently). So I don't see why your services wouldn't be restarted when you restart the instance; is there nothing in the service logs or /var/log/messages to give you a clue ? – gareth_bowles Jan 6 '10 at 17:12
feedback
up vote 0 down vote

When you start an EBS-backed instance all of the installed services should start. I start/stop several instances (LAMP servers) every day and apache, mysql, and everything comes right up.

On a few occasions I did have to reboot the instance for a few services to come up. I attribute this to lag connecting to the EBS and therefore not able to reach the appropriate files in time.

link|improve this answer
feedback

Your Answer

 
or
required, but never shown
discard

Not the answer you're looking for? Browse other questions tagged or ask your own question.