Azure Functions
An Azure service that provides an event-driven serverless compute platform.
5,939 questions
Random certificate chain errors in Azure function apps
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Ahmet Altun
0
Reputation points
Hi,
We are calling an on-prem gRPC service from Azure function app (running on Linux app service plan).
The on -prem grpc service has an self signed certificate (not a vendor cert).
In order to pass SSL verification successfully - all the intermediate and root parents of the remote certificate are imported to function separately - The thumbprints of the certificates are referred via WEBSITE_LOAD_ROOT_CERTIFICATES env variable.
Even though this configuration enables smooth SSL communication, it fails randomly complaining about "The remote certificate is invalid because of errors in the certificate chain: PartialChain". This random error occurs at an arbitrary time - without us changing nothing - and immediately resolved once app is restarted. Do you have any idea why it might happen and how to solve it?
Azure Functions
{count} votes
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Ryan Hill 30,281 Reputation points Microsoft Employee Moderator2024-07-15T20:58:52.92+00:00 Hi @Ahmet Altun, when the function is in a failed state, can you run
openssl s_client -servername FQDN -connect FQDN:443 -showcertsfrom the function app to get more details of certificate failure? -
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(179.20000000000002, 4%, 27%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMV%3C/text%3E%3C/svg%3E)
Manikandan V 5 Reputation points2024-07-15T21:17:59.34+00:00 It looks like network issue. Implement retry logic with exponential backoff in your function app to handle transient network issues gracefully.
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Manikandan V 5 Reputation points
2024-07-15T21:19:09.9033333+00:00 It looks like network issue. Implement retry logic with exponential backoff in your function app to handle transient network issues gracefully.
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