Add possibility to change drain command parameters (#9)

* Add possibility to change drain command parameters

* fixup! Add possibility to change drain command parameters

* fixup! Add possibility to change drain command parameters

* fixup! Add possibility to change drain command parameters

* fixup! Add possibility to change drain command parameters

Author: wandera-ci

README.md

@@ -41,6 +41,15 @@ To achieve this, add the following flag to your Kubelet:
 --node-labels="node-role.kubernetes.io/spot-worker=true"
 ```
 
+#### Configuration
+
+To define any custom parameters to the drain command you can use `DRAIN_PARAMETERS` environment property. If not defined, default parameters are `--grace-period=120 --force --ignore-daemonsets`.
+```yaml
+env:
+  - name: DRAIN_PARAMETERS
+    value: '--grace-period=120 --force --ignore-daemonsets --delete-local-data'
+```
+
 ## Related
 - [K8s Spot Rescheduler](https://github.com/pusher/k8s-spot-rescheduler): Move nodes from on-demand instances to spot instances when space is available.
 

deploy/daemonset.yaml

@@ -23,6 +23,9 @@ spec:
             valueFrom:
               fieldRef:
                 fieldPath: spec.nodeName
+          # Parameters to drain commmand can be adjusted
+          - name: DRAIN_PARAMETERS
+            value: '--grace-period=120 --force --ignore-daemonsets'
         resources:
           requests:
             cpu: 5m

docker_entrypoint.py

@@ -13,6 +13,8 @@ def main():
 
     node_name = getenv('NODE_NAME')
 
+    drain_parameters = getenv('DRAIN_PARAMETERS', '--grace-period=120 --force --ignore-daemonsets')
+
     print('Watching for termination notice on node %s' % node_name)
 
     counter = 0
@@ -22,9 +24,8 @@ def main():
             "http://169.254.169.254/latest/meta-data/spot/termination-time"
         )
         if response.status_code == 200:
-            kube_command = ['kubectl', 'drain', node_name,
-                            '--grace-period=120', '--force',
-                            '--ignore-daemonsets']
+            kube_command = ['kubectl', 'drain', node_name]
+            kube_command += drain_parameters.split()
 
             print("Draining node: %s" % node_name)
             result = call(kube_command)