Fix preStop behavior for KEDA scale-down

Updated the preStop hook to decouple it from Selenium node command-line arguments. This prevents random node terminations during KEDA scale-down.

Author: kool79

website_and_docs/content/blog/2022/scaling-grid-with-keda.md

@@ -118,7 +118,7 @@ spec:
         lifecycle:
           preStop:
             exec:
-              command: ["/bin/sh", "-c", "curl --request POST 'localhost:5555/se/grid/node/drain' --header 'X-REGISTRATION-SECRET;'; tail --pid=$(pgrep -f '[n]ode --bind-host false --config /opt/selenium/config.toml') -f /dev/null; sleep 30s"]
+              command: ["/bin/sh", "-c", "curl --request POST 'localhost:5555/se/grid/node/drain' --header 'X-REGISTRATION-SECRET;'; while curl -fs localhost:5555/status >/dev/null; do sleep 1; done; sleep 10"]
 ```
 
 #### Breaking this down
@@ -219,4 +219,4 @@ spec:
               command: ["/bin/sh", "-c", "curl --request POST 'localhost:5555/se/grid/node/drain' --header 'X-REGISTRATION-SECRET;'; tail --pid=$(pgrep -f '[n]ode --bind-host false --config /opt/selenium/config.toml') -f /dev/null; sleep 30s"]
 ```
 
-That is it, your Selenium Grid pods should now scale up and down properly without any lost sessions!
+That is it, your Selenium Grid pods should now scale up and down properly without any lost sessions!