Linux Wordpress App Service - View log output from Startup.sh/Startup command

Question

Stack: Wordpress/PHP 8.3

container: mcr.microsoft.com/appsvc/wordpress-debian-php:8.3

How am I able to output to either the devops console or the SCM log stream from startup.sh or the Startup command?

I simply have an 'echo "TEST STARTUP"' in my startup.sh and Startup command, but I cannot see the text output anywhere - SCM, Log Stream in the Azure Portal, Devops. This includes both when I restart the app service and when deploying to the app service from devops.

I know the commands are running because when I set either of them to

echo "TEST STARTUP">>/home/LogFiles/StartupLog.txt

I see the StartupLog.txt file appear and "TEST STARTUP" as the content

Ideally I would like to be able to output log entries to either one of the SCM log files, or somehow get it to appear in the Devops console during deployments

Answer 1

Hi there,

On Linux App Service, only whatever the main container process writes to stdout or stderr is captured by Log stream (az webapp log tail) and the SCM Docker logs. Anything your startup.sh echoes before that main process is launched never reaches the pipeline—so you won’t see echo "TEST STARTUP" in Log stream or your Azure DevOps console.

How to surface your startup.sh output

Turn on log streaming (once per app)

Portal ▸ Monitoring ▸ App Service logs
─ Application logging (Filesystem) → On

Or:

az webapp log config -g <rg> -n <app> --application-logging filesystem

Redirect everything in startup.sh to stdout / stderr

# startup.sh
exec 1>/dev/stdout 2>/dev/stderr     # route subsequent output
echo "==== WordPress container initialising ===="

or, for a single line

echo "TEST STARTUP" >&2   # write explicitly to stderr

Tail the stream

az webapp log tail -g <rg> -n <app>

(or open Monitoring ▶ Log stream in the portal).

If you still need early-startup diagnostics

Writing to a file under /home/LogFiles/ (e.g., echo … >> /home/LogFiles/StartupLog.txt) is fine for debugging; you can open the file via Kudu/SSH. But for day-to-day visibility, redirecting to stdout/stderr is the cleanest approach.

Why nothing shows in the Azure DevOps release logs DevOps captures the build/deploy pipeline only—it doesn’t stream what happens inside the running container. Use Log stream or Azure Monitor for runtime output.

Hope that clears things up!

Best Regards,

Jerald Felix