Azure container app recreates replicas once a week. Why?

Question

Azure container app recreates replicas once a week. Why?

Erinda Jaupaj 0

I have created 2 Container App Environments and each one has 3 container apps.

I have noticed that every Friday

21/03/2025, 01:40:12

28/03/2025, 19:54:18

04/04/2025, 03:53:11

11/04/2025, 19:54:51

replicas from both environments and for all container apps get recreated at the same time.

First environment has a low level traffic and I never go above cpu or memory limit.

Second environment has almost no traffic at all as it is used just for dev purposes.

All container apps are in the same zone.

Why does this happen?

If they are scheduled updates from azure side where can I see them?

Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-14T12:17:39.4533333+00:00

Hello @Erinda Jaupaj,
It appears that your Azure Container Apps are undergoing routine maintenance or automatic replica replacement on a weekly basis. This is likely due to scheduled platform updates from Azure, which regularly refreshes replicas to maintain performance, stability, and security.

To better understand these events, you can check a few things. Subscribe to Azure Service Health notifications to stay informed about planned maintenance, review the Activity Log in Azure Monitor for any recorded updates, and check your app’s scaling rules and revision settings, as automatic scaling can also trigger replica refreshes. These updates are a normal part of Azure’s ongoing maintenance to keep your services running smoothly and securely.

For further clarification, please refer to the following documentations:

https://learn.microsoft.com/en-us/azure/container-apps/planned-maintenance

https://learn.microsoft.com/en-us/azure/container-apps/scale-app?pivots=azure-cli

I hope this helps resolve your issue. Feel free to reach out if you have further concerns.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-15T10:25:31.2866667+00:00

Hi @Erinda Jaupaj,

Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.
Erinda Jaupaj 0 Reputation points

2025-04-15T14:25:30.4733333+00:00

Thank you! I'll let you know after this Friday. At the moment I'll try setting up a maintenance window and see if that will have any effect.

Related to Azure Service Health I do not see anything related to azure container apps, at least in the health history.

In Monitor -> Activity Log, I did find Create or Update Network Security Group related to both aks-managed-clusters. But I do see this in other dates as well, and it does not have the same effect as each Friday.

About scaling rules , I do not have any. Min and Max are set on the same value. If this was the case, the replica recreation will be in different time. Still does not explain the recreation on 2 different aks cluster at the same exact time.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-17T14:49:28.93+00:00

Hi @Erinda Jaupaj,
We are currently awaiting your response to proceed further. Please let us know if there are any questions or additional information you need from our side.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-18T13:35:50.9466667+00:00

Hi @Erinda Jaupaj,

Just following up again to see if you were able to resolve the issue or if there's anything else I can assist you with. Let me know if you need further help.
Erinda Jaupaj 0 Reputation points

2025-04-24T13:52:38.9166667+00:00

In the end it is due to scheduled platform updates from Azure.
Is this something that needs to happen every week? Is there a possibility to do it once a month?
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-28T11:28:57.35+00:00

Hello @Erinda Jaupaj,
The regular recreation of your container app replicas is most likely due to scheduled platform maintenance performed by Azure. These updates are handled automatically by the platform to ensure security, stability, and performance of the underlying infrastructure. While you’re noticing this happening weekly, the exact timing and frequency can vary and are not directly configurable by users.

Currently, Azure doesn’t offer a way to reduce or change how often these maintenance events occur, for example, setting them to monthly. This is part of the managed nature of the Azure Container Apps service. To stay informed, you can use Azure Service Health to receive notifications about planned maintenance. .
Erinda Jaupaj 0 Reputation points

2025-04-29T09:51:34.4866667+00:00

The problem that comes with how this updates are made is that it seems like the existing replica gets deleted and then created.
What I'd like to see is for it to create a new one and after the new one is active to delete one of the old replicas. Not sure if it is possible to add a "rule" on how this updates should be applied.
Like in place replacement or scale up and scale down behaviour.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-29T13:57:15.7666667+00:00

Hi @Erinda Jaupaj,
The regular recreation of your container app replicas is most likely due to platform maintenance that Azure performs automatically to ensure security, performance, and stability. While you’ve noticed this happening weekly, the timing and frequency of these updates can vary and are managed entirely by the Azure platform. There is not a way to change or reduce how often these updates happen, as Azure Container Apps is a fully managed service and handles infrastructure behind the scenes.

To stay informed, we recommend setting up Azure Service Health alerts, which will notify you about any planned maintenance affecting your resources. You can also check the Azure Activity Log for more details about what’s happening during these times.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-30T13:40:34.4033333+00:00

Hello @Erinda Jaupaj,
If you had a chance to review my response to your question and found it helpful, please consider clicking "Upvote" on my post. Let us know if you need any further assistance.

Your answer

Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-14T12:17:39.4533333+00:00

Hello @Erinda Jaupaj,
It appears that your Azure Container Apps are undergoing routine maintenance or automatic replica replacement on a weekly basis. This is likely due to scheduled platform updates from Azure, which regularly refreshes replicas to maintain performance, stability, and security.

To better understand these events, you can check a few things. Subscribe to Azure Service Health notifications to stay informed about planned maintenance, review the Activity Log in Azure Monitor for any recorded updates, and check your app’s scaling rules and revision settings, as automatic scaling can also trigger replica refreshes. These updates are a normal part of Azure’s ongoing maintenance to keep your services running smoothly and securely.

For further clarification, please refer to the following documentations:

https://learn.microsoft.com/en-us/azure/container-apps/planned-maintenance

https://learn.microsoft.com/en-us/azure/container-apps/scale-app?pivots=azure-cli

I hope this helps resolve your issue. Feel free to reach out if you have further concerns.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-15T10:25:31.2866667+00:00

Hi @Erinda Jaupaj,

Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.
Erinda Jaupaj 0 Reputation points

2025-04-15T14:25:30.4733333+00:00

Thank you! I'll let you know after this Friday. At the moment I'll try setting up a maintenance window and see if that will have any effect.

Related to Azure Service Health I do not see anything related to azure container apps, at least in the health history.

In Monitor -> Activity Log, I did find Create or Update Network Security Group related to both aks-managed-clusters. But I do see this in other dates as well, and it does not have the same effect as each Friday.

About scaling rules , I do not have any. Min and Max are set on the same value. If this was the case, the replica recreation will be in different time. Still does not explain the recreation on 2 different aks cluster at the same exact time.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-17T14:49:28.93+00:00

Hi @Erinda Jaupaj,
We are currently awaiting your response to proceed further. Please let us know if there are any questions or additional information you need from our side.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-18T13:35:50.9466667+00:00

Hi @Erinda Jaupaj,

Just following up again to see if you were able to resolve the issue or if there's anything else I can assist you with. Let me know if you need further help.
Erinda Jaupaj 0 Reputation points

2025-04-24T13:52:38.9166667+00:00

In the end it is due to scheduled platform updates from Azure.
Is this something that needs to happen every week? Is there a possibility to do it once a month?
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-28T11:28:57.35+00:00

Hello @Erinda Jaupaj,
The regular recreation of your container app replicas is most likely due to scheduled platform maintenance performed by Azure. These updates are handled automatically by the platform to ensure security, stability, and performance of the underlying infrastructure. While you’re noticing this happening weekly, the exact timing and frequency can vary and are not directly configurable by users.

Currently, Azure doesn’t offer a way to reduce or change how often these maintenance events occur, for example, setting them to monthly. This is part of the managed nature of the Azure Container Apps service. To stay informed, you can use Azure Service Health to receive notifications about planned maintenance. .
Erinda Jaupaj 0 Reputation points

2025-04-29T09:51:34.4866667+00:00

The problem that comes with how this updates are made is that it seems like the existing replica gets deleted and then created.
What I'd like to see is for it to create a new one and after the new one is active to delete one of the old replicas. Not sure if it is possible to add a "rule" on how this updates should be applied.
Like in place replacement or scale up and scale down behaviour.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-29T13:57:15.7666667+00:00

Hi @Erinda Jaupaj,
The regular recreation of your container app replicas is most likely due to platform maintenance that Azure performs automatically to ensure security, performance, and stability. While you’ve noticed this happening weekly, the timing and frequency of these updates can vary and are managed entirely by the Azure platform. There is not a way to change or reduce how often these updates happen, as Azure Container Apps is a fully managed service and handles infrastructure behind the scenes.

To stay informed, we recommend setting up Azure Service Health alerts, which will notify you about any planned maintenance affecting your resources. You can also check the Azure Activity Log for more details about what’s happening during these times.
Ranashekar Guda 1,360 Reputation points Microsoft External Staff Moderator

2025-04-30T13:40:34.4033333+00:00

Hello @Erinda Jaupaj,
If you had a chance to review my response to your question and found it helpful, please consider clicking "Upvote" on my post. Let us know if you need any further assistance.

Share via

Azure container app recreates replicas once a week. Why?

Your answer