Very slow to deploy after updating WEBSITE_RUN_FROM_PACKAGE

To deploy my Azure Function I follow what seems to be the best practice right now from Microsoft. I upload a zip file to blob storage with the code and then I update the WEBSITE_RUN_FROM_PACKAGE setting on the Azure Function (on a deployment slot, to be specific)

Then, after some time, the latest version is deployed. I can confirm this by querying a version number on the API.

This all works!

However, some times it takes a long time. In my most recent try, it took more than 7 minutes. This is not a very large package (7 MB) with about 100 Function endpoints. Much of the time it takes about 2 minutes but some times it takes much longer.

It is my feeling that it takes LONG time about 1 out of 3 times. And then short time (2 minutes) about 2 of 3 times.

Does anyone know why it doesn't work well much of the time? And/or has any idea how I can troubleshoot this. I don't know where or if I can access any log about how the function discovers the new package file and what it is waiting for.

--

Edit: I found this in the deployment log through CLI.

  {
    "active": true,
    "author": "N/A",
    "author_email": "N/A",
    "complete": true,
    "deployer": "Push-Deployer",
    "end_time": "2023-05-20T13:51:52.9356458Z",
    "id": "89feddbf-c575-4d32-b795-d3d6111ecee5",
    "is_readonly": true,
    "is_temp": false,
    "last_success_end_time": "2023-05-20T13:51:52.9356458Z",
    "log_url": "https://appname-slotname.scm.azurewebsites.net/api/deployments/8feddbf-c575-4d32-b795-d3d6111ecee5/log",
    "message": "Created via a push deployment",
    "progress": "",
    "received_time": "2023-05-20T13:51:31.0878136Z",
    "site_name": "appname",
    "start_time": "2023-05-20T13:51:32.9850841Z",
    "status": 4,
    "status_text": "",
    "url": "https://appname-slotname.scm.azurewebsites.net/api/deployments/8feddbf-c575-4d32-b795-d3d6111ecee5"
  }

I am guessing that "active" means this deployment is currently the one running on the deployment slot. And that fits because my new deployments, which are taking a long time, do not show up here until maybe shortly before they are actually completed.

I have tried manually restarting the deployment slot and manually saving the app settings with no difference.

You're right, Running the Function app deployment from package makes the deployment faster. But there are several other factors, That you should consider. As you are transferring the Zip from your blob storage to Azure Functions, There might be some delay during the transfer, Between Azure storage account and Azure Functions resource.

If your Function app has dependency or some packages there might be some delay in deployment of these packages, Thus make sure you have your function dependent packages managed properly.

You can consider upgrading your Function app to Premium plan or dedicated App service plan as Premium Function plan reduces Cold start and has always ready instances which makes your deployment and Functions running faster than Consumption based plan. Refer below:-

Along with WEBSITE_RUN_FROM_PACKAGE setting set to 1, Add the below setting to make your deployment faster as a best practice:-

Reference:- MS Q & A forum answer by MayankBargali-MSFT

> txt
> SCM_DO_BUILD_DURING_DEPLOYMENT : TRUE
>
>
>

I deployed one Function via zip deployment by using the command below:-

Command reference

> bash
> az functionapp deployment source config-zip -g siliconrg54 -n
> siliconfunc65 --src "<PATH>\repos\FunctionApp7.zip"
>

In order to view the Deployment logs of your zip deployment Refer below:-

Visit Development tools > Advanced Tools > Go > Kudu environment will open like below:-

You can click on the links below REST API sections to get insights on your deployment.

To get the Deployment logs > Click on Tools > Diagnostic dump all the diagnostic logs including Deployment logs will be downloaded locally, Refer below:-

You can select the downloaded dump > LogFiles > Monaco > And get the deployment timestamp logs of your Function like below:-

In your Kudu tool, You can click on tools > Zip push Deploy to check your zip deployment logs like below:-

> Zip Push Deployment reference

> You can refer this answer by MayankBargali-MSFT and this Azure Functions Best Practices