Performing a No-Op with chef-client using JSON
There could be a case where you may want to perform a chef-client run so it doesn't actually change any resources.
I previously wanted to do this, but encountered a bit of a funny gotcha, so decided to document it.
Let us assume that our regular cookbook JSON configuration is:
{
"java": {
"jdk_version": 7
},
"run_list": [
"java"
]
}
Which performs the following chef-client run:
$ chef-client -j full-run.json
Starting Chef Client, version 13.6.4
resolving cookbooks for run list: ["java"]
Synchronizing Cookbooks:
- java (3.2.0)
- windows (5.2.3)
- homebrew (5.0.8)
Installing Cookbook Gems:
Compiling Cookbooks...
Converging 7 resources
Recipe: java::notify
* log[jdk-version-changed] action nothing (skipped due to action :nothing)
Recipe: java::openjdk
* apt_repository[openjdk-r-ppa] action add
...
Running handlers:
Running handlers complete
Chef Client finished, 5/12 resources updated in 04 minutes 04 seconds
Expected Solution
The no-op configuration I tried at first was, as simple as I could think, an empty JSON object:
{}
But unfortunately that doesn't quite work:
$ chef-client -j noop.json
Starting Chef Client, version 13.6.4
resolving cookbooks for run list: ["java"]
Synchronizing Cookbooks:
- java (3.2.0)
- windows (5.2.3)
- homebrew (5.0.8)
Installing Cookbook Gems:
Compiling Cookbooks...
Converging 7 resources
Recipe: java::notify
* log[jdk-version-changed] action nothing (skipped due to action :nothing)
Recipe: java::openjdk
* apt_repository[openjdk-r-ppa] action add
...
Recipe: java::set_java_home
* directory[/etc/profile.d] action create (up to date)
* template[/etc/profile.d/jdk.sh] action create (up to date)
Running handlers:
Running handlers complete
Chef Client finished, 0/11 resources updated in 06 seconds
Actual Solution
Instead, we need to have an empty JSON object with a zero-length run_list:
{
"run_list": []
}
This then gives us a true no-op:
$ chef-client -j real-noop.json
Starting Chef Client, version 13.6.4
resolving cookbooks for run list: []
Synchronizing Cookbooks:
Installing Cookbook Gems:
Compiling Cookbooks...
Converging 0 resources
Running handlers:
Running handlers complete
Chef Client finished, 0/0 resources updated in 01 seconds
