6-system-fix.md

Check and fix

This tutorial covers:

1. Verifying that the system is running according to expectations
2. Fixing the system after two containers are killed off

Verify sudc is running

OS X: open http://$(boot2docker ip):8000

Linux: open localhost:8000

Let's double check that sudc is working as expected by running:

nscale system check sudc development

You should see the following output:

Looking good! No deviation detected

The check command runs a system analysis to verify that everything is looking good! We can view the output of that analysis by running:

nscale system analyze sudc development

Kill two of the containers

Now we'll kill the web and doc-srv containers:

docker ps
docker kill <web container id>
docker kill <doc container id>

Then we'll verify sudc is not running:

OS X: open http://$(boot2docker ip):8000

Linux: open localhost:8000

The address should be unreachable.

Now let's do the check again:

nscale system check sudc development

We should see some output similar to the following:

Deviation from deployed revision detected!
Remedial action plan as follows:

execution plan: 
Command                        Id                                                
add                            doc-c31f912e$77c4014bef47deb4fef3af579f2959457c05…
start                          doc-c31f912e$77c4014bef47deb4fef3af579f2959457c05…
link                           doc-c31f912e$77c4014bef47deb4fef3af579f2959457c05…
add                            web-5a16c094$3779d219ae5108029625d849e15bbd1ef3be…
start                          web-5a16c094$3779d219ae5108029625d849e15bbd1ef3be…
link                           web-5a16c094$3779d219ae5108029625d849e15bbd1ef3be…

operations: 
Host                 Command                                                                                                                                               
localhost            docker run  -p 9002:9002 -d localhost:8011/sudc/doc-77c4014bef47deb4fef3af579f2959457c058ce8 node /srv/doc-srv.js && docker tag localhost:8011/sudc/d…
localhost            docker run  -p 8000:8000 -d localhost:8011/sudc/web-3779d219ae5108029625d849e15bbd1ef3bed74e /bin/bash /web/run.sh && docker tag localhost:8011/sudc/…

run 'system fix' to execute

System fix and sudc redeploy

Let's do a system fix to get sudc up and running again:

nscale system fix sudc development

And check sudc is working as expected again:

nscale system check sudc development

OS X: open http://$(boot2docker ip):8000

Linux: open localhost:8000

Next up: exercise 7