Configurable settings

David Ebbo edited this page Sep 11, 2018 · 89 revisions

There are various things that you can configure using App Settings, which you can find on the Configure page in the Azure portal.

Repository and deployment related settings

Note that in addition to using App Settings, you can specify those settings in your .deployment file. This is useful if you want the setting to be part of your repository.

Adding flags to the msbuild command line

Use this flag to add things at the end of the msbuild command line, such that it overrides any previous parts of the default command line.

e.g. to choose the Debug build configuration (default is Release) and apply a chained config transform, you could have:

[config]
SCM_BUILD_ARGS=-p:Configuration=Debug;PublishProfile=MyChainedTransform

As another example, to do a clean build, you can use:

[config]
SCM_BUILD_ARGS=-t:Clean;Compile

Taking over the script generator command line

Kudu uses the azure site deploymentscript command described here to generate a deployment script. By default, it figures out what parameters to pass by looking at the files in the repo to determine the project type (e.g. Node, ASP.NET, ...).

But in some cases, you may want to override that and take control of the command line, which you can do using this setting.

e.g. to force your repo to be treated as a plain web site (no build), you can use:

SCM_SCRIPT_GENERATOR_ARGS=--basic -p FolderToDeploy

Enable/disable build actions

Depending on the type of site you are deploying and the deployment method you are using, Kudu will executes build steps on your site during deployment, such as npm install or dotnet build/dotnet publish. To disable this, such as when performing deployment of an already-built site, set:

SCM_DO_BUILD_DURING_DEPLOYMENT=false

This provides the same behavior as the SCM_SCRIPT_GENERATOR_ARGS=--basic example above.

The default for zip deployments is false, and for all other deployment methods is true.

Take over the whole deployment script

See Customizing deployments for details. e.g.

COMMAND=deploy.cmd

Changing the repo and deployment paths, and not using a repo at all

Please see Deploying inplace and without repository for information on using the SCM_REPOSITORY_PATH, SCM_NO_REPOSITORY, PROJECT and SCM_TARGET_PATH flags.

Disabling the update of git submodules

By default, Kudu automatically update submodules before doing a deployment. To turn that off:

SCM_DISABLE_SUBMODULES=1

Note: this is support as an Azure App Setting, but not in the .deployment file.

Using a git shallow clone in Continuous Deployment scenarios

For large repos, you can make Kudu use a shallow clone when it clones your repo from GitHub or Bitbucket, which can save disk space. Shallow clones can be tricky, so make sure you understand what they are before using this. It is off by default. To turn it on:

SCM_USE_SHALLOW_CLONE=1

Note: this is support as an Azure App Setting, but not in the .deployment file.

Don't touch web.config at the end of the deployment

By default, it gets touched. Sometimes, it's sub-optimal as it can causes an unnecessary restart. To avoid it, set:

SCM_TOUCH_WEBCONFIG_AFTER_DEPLOYMENT=0

Customize post deployment action directory

See Post Deployment Action Hooks for details.

Don't build and deploy during git push

With this flag, a git push updates the server repo, but does not trigger a deployment. Note that this only applies when git pushing directly to the Kudu git endpoint, and not in continuous integration scenarios like GitHub/Bitbucket.

SCM_DISABLE_DEPLOY_ON_PUSH=1

Add custom delay before deployment

By default, kudu starts deployment as soon as git repository is updated. You can delay this deployment for X seconds, X being a random number between 0 and SCM_MAX_RANDOM_START_DELAY

SCM_MAX_RANDOM_START_DELAY=100

Automatically run funcpack on Function App git deployments

funcpack runs WebPack, turning large npm trees into single files, which can improve cold start greatly.

SCM_USE_FUNCPACK=1

Diagnostic related settings

Changing the trace level

By default, it is set to 1, but you can get more tracing with higher values, up to 4. e.g.

SCM_TRACE_LEVEL=4

Changing the timeout before external commands are killed

By default, when your build process launches some command, it's allowed to run for up to 60 seconds without producing any output. If that is not long enough, you can make it longer, e.g. to make it 10 minutes:

SCM_COMMAND_IDLE_TIMEOUT=600

Note that on Azure, there is a general idle request timeout that will cause clients to get disconnected after 230 seconds. However, the command will still continue running server-side after that.

Changing the timeout of the log streaming feature

When using the log streaming feature, by default it times out after 30 minutes of inactivity. To change it to 15 minutes (unit is seconds):

SCM_LOGSTREAM_TIMEOUT=900

Other Kudu settings

Site Extensions gallery feed url

Each site gets the site extensions feed from a configurable Url. If it is not set, the behavior is equivalent to

SCM_SITEEXTENSIONS_FEED_URL=https://www.nuget.org/api/v2/

For reference, the old feed was:

SCM_SITEEXTENSIONS_FEED_URL=http://www.siteextensions.net/api/v2/

Runtime settings

The following settings must be set in the Azure App Settings, and cannot be overridden in the .deployment file (since they are not deployment settings)

Using git.exe instead of libgit2sharp for git operations

SCM_USE_LIBGIT2SHARP_REPOSITORY=0

Change the Node version

Used the change the version of Node that is used by default

WEBSITE_NODE_DEFAULT_VERSION=0.10.5

Change the Npm version

Used the change the version of Npm that is used by default

WEBSITE_NPM_DEFAULT_VERSION=1.2.30

Add user profile support for a site

See this forum thread for details.

Important: this is only available for sites running in Basic or Standard mode.

WEBSITE_LOAD_USER_PROFILE=1

Turning on the 'local cache' feature.

This feature copies the site bits to the faster local drive before running them. Se this post for more info.

WEBSITE_LOCAL_CACHE_OPTION=Always

Also, the size of the cache can be changed (default is 300MB):

WEBSITE_LOCAL_CACHE_SIZEINMB=500

Turning on the 'dynamic cache' feature.

Full content caching: caches both file content and directory/file metadata (timestamps, size, directory content):

WEBSITE_DYNAMIC_CACHE=1

Directory metadata caching: will not cache content of the files, only the directory/file metadata (timestamps, size, directory content). That results in much less local disk use:

WEBSITE_DYNAMIC_CACHE=2

Enabling the new http scaling mode

WEBSITE_HTTPSCALEV2_ENABLED=1

Using Run-From-Zip feature

https://github.com/Azure/app-service-announcements/issues/84

WEBSITE_USE_ZIP=https://davidebbostorage.blob.core.windows.net/content/SampleCoreMVCApp.zip?st=2018-02-13T09%3A48%3A00Z&se=2044-06-14T09%3A48%3A00Z&sp=rl&sv=2017-04-17&sr=b&sig=bNrVrEFzRHQB17GFJ7boEanetyJ9DGwBSV8OM3Mdh%2FM%3D

Disable the use of private site extensions

WEBSITE_PRIVATE_EXTENSIONS=0

Load certificates in the Web App

See this post for details. First, the certs must be uploaded to the App Service Plan. Than App settings need to be set:

WEBSITE_LOAD_CERTIFICATES=*

or the specific thumbprints for just one

WEBSITE_LOAD_CERTIFICATES=ABCABCABCABCABCABCABCABCABCABCABCABCABCABC,DEFDEFDEFDEFDEFDEFDEFDEFDEFDEFDEFDEFDEFDEF

Set the time zone

By default, the time zone is always UTC, but you can change it. You can get the list of valid values from this article (warning this other article shows slightly different strings which do not work!). You can also find the list in your registry under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones. If the string is not recognized, it falls back to UTC. The best way to test that it works is to type time from Kudu console.

Examples:

WEBSITE_TIME_ZONE=Eastern Standard Time
WEBSITE_TIME_ZONE=AUS Eastern Standard Time

Note that there appears to be an issue that makes it not work when using DateTimeOffset.Now. See this question for details.

Increase the time before the scm site is timeout

By default, even on dedicated, the timeout is 20 minutes. But you can increase it:

WEBSITE_SCM_IDLE_TIMEOUT_IN_MINUTES=30

Note that this is not needed if you are also using the Always On feature.

Disable the placeholder site optimization on Consumption Function Apps

It's an optimization that improves the cold start. In case it causes problems, it can be disabled:

WEBSITE_USE_PLACEHOLDER=0

Disable overlapped recycling

Overlapped recycling makes it so that before the current instance on an app is shut down, a new instance starts. It can in some cases cause file locking issues, in which case you can try turning it off:

WEBSITE_DISABLE_OVERLAPPED_RECYCLING=1

Diagnostics related settings

The name (or relative path to the LogDirectory) of the file where internal errors are logged, for troubleshooting the listener:

DIAGNOSTICS_LASTRESORTFILE=logging-errors.txt

The settings file, relative to the web app root:

DIAGNOSTICS_LOGGINGSETTINGSFILE=..\diagnostics\settings.json

The log folder, relative to the web app root:

DIAGNOSTICS_TEXTTRACELOGDIRECTORY=..\..\LogFiles\Application

Maximum size of the log file (Default: 128 kb):

DIAGNOSTICS_TEXTTRACEMAXLOGFILESIZEBYTES=200000

Maximum size of the log folder (Default: 1 MB):

DIAGNOSTICS_TEXTTRACEMAXLOGFOLDERSIZEBYTES=2000000

Timeout in milliseconds to keep application logging on (Default is 43200000, which is 12 hours):

DIAGNOSTICS_TEXTTRACETURNOFFPERIOD=43200000

Don't use the SCM site for WebDeploy

WEBSITE_WEBDEPLOY_USE_SCM=false

Attempt to rename DLLs if they can't be copied during a WebDeploy deployment

Note: this only applies if you don't set WEBSITE_WEBDEPLOY_USE_SCM=false

MSDEPLOY_RENAME_LOCKED_FILES=1

Use the same process for the user site and the scm site

WEBSITE_DISABLE_SCM_SEPARATION=true

When separation enabled (the default), the main site and scm site run in different sandboxes. Some resulting behavior:

  • With separation, when you stop the site, the scm site is still running, and you can continue to use git and msdeploy.
  • With separation, the Main and scm sites each have their own local files. So you won't see the Main site's temp files from Kudu console.

Please be aware that turning off separation is considered to be a legacy mode that is no longer fully supported.

Pre-start the SCM site as part of site creation (needs to be set in the site creation call)

WEBSITE_START_SCM_ON_SITE_CREATION=true

Disable the generation of bindings in applicationhost.config

Important: if using the following two settings, make sure to set them equally on all slots

This can be useful in some scenarios where they can get out of sync. This is also useful to workaround post-swap site slot restart.

WEBSITE_SKIP_ALL_BINDINGS_IN_APPHOST_CONFIG=1

There is another setting that can be used as an alternative to the previous one to generate just one fixed binding, to make WCF happy in some scenarios:

WEBSITE_ADD_SITENAME_BINDINGS_IN_APPHOST_CONFIG=1

Limit the scaling of function apps

See the WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT setting detailed here in the Functions wiki.

Linux on App Service settings

See https://docs.microsoft.com/en-us/azure/app-service/containers/app-service-linux-faq for details on WEBSITES_ENABLE_APP_SERVICE_STORAGE, WEBSITES_CONTAINER_START_TIME_LIMIT, WEBSITES_PORT and other settings.

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