Azure Kubernetes Service
An Azure service that provides serverless Kubernetes, an integrated continuous integration and continuous delivery experience, and enterprise-grade security and governance.
Azure Monitor pods CrashLoopBackOff with iptables
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Julien Taveau
0
Reputation points
Hi,
I added a new node to my Arc enabled K8s cluster, the ama-* pods seems not to work, and are in CrashLoopBackOff state.
ama-metrics-node
kubectl logs ama-metrics-node-cg6t5 -n kube-system -c arc-msi-adapter
MICROSOFT SOFTWARE LICENSE TERMS
MICROSOFT Azure Arc for Kubernetes
__________________________________
This software is licensed to you as part of your or your company's subscription license for Microsoft Azure Services. You may only use the software with Microsoft Azure Services and subject to the terms and conditions of the agreement under which you obtained Microsoft Azure Services. If you do not have an active subscription license for Microsoft Azure Services, you may not use the software. Microsoft Azure Legal Information: https://azure.microsoft.com/en-us/support/legal/
F0728 13:22:06.491091 1 main.go:61] error modifying iptable rules: error adding rules to custom chain: running [/usr/sbin/iptables -t nat -N aad-metadata --wait]: exit status 4: iptables v1.8.10 (nf_tables): Could not fetch rule set generation id: Invalid argument
ama-logs
kubectl logs ama-logs-l2zxd -n kube-system -c addon-token-adapter
MICROSOFT SOFTWARE LICENSE TERMS
MICROSOFT Azure Arc for Kubernetes
__________________________________
This software is licensed to you as part of your or your company's subscription license for Microsoft Azure Services. You may only use the software with Microsoft Azure Services and subject to the terms and conditions of the agreement under which you obtained Microsoft Azure Services. If you do not have an active subscription license for Microsoft Azure Services, you may not use the software. Microsoft Azure Legal Information: https://azure.microsoft.com/en-us/support/legal/
F0728 13:31:13.090395 1 main.go:61] error modifying iptable rules: error adding rules to custom chain: running [/usr/sbin/iptables -t nat -N aad-metadata --wait]: exit status 4: iptables v1.8.10 (nf_tables): Could not fetch rule set generation id: Invalid argument
ama-logs-rs
kubectl logs ama-logs-rs-657758c54c-qc8dl -n kube-system -c addon-token-adapter
MICROSOFT SOFTWARE LICENSE TERMS
MICROSOFT Azure Arc for Kubernetes
__________________________________
This software is licensed to you as part of your or your company's subscription license for Microsoft Azure Services. You may only use the software with Microsoft Azure Services and subject to the terms and conditions of the agreement under which you obtained Microsoft Azure Services. If you do not have an active subscription license for Microsoft Azure Services, you may not use the software. Microsoft Azure Legal Information: https://azure.microsoft.com/en-us/support/legal/
F0728 13:36:16.298418 1 main.go:61] error modifying iptable rules: error adding rules to custom chain: running [/usr/sbin/iptables -t nat -N aad-metadata --wait]: exit status 4: iptables v1.8.10 (nf_tables): Could not fetch rule set generation id: Invalid argument
I also had an issue with svclb-traefik, blacklisting nf_tables solved the issue.
Could you help me, please?
Azure Kubernetes Service
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Vinod Pittala 6,130 Reputation points Microsoft External Staff Moderator2025-07-28T15:10:21.8333333+00:00 Hello Julien Taveau,
The
CrashLoopBackOffstate for the Azure Monitor pods, such asama-metrics-nodeandama-logs, appears to be related to issues with iptables. The logs indicate that there are errors modifying iptable rules, specifically when trying to add rules to a custom chain, which is causing the pods to fail.To resolve this issue, you may need to ensure that the
iptablesmodule is correctly configured on your nodes. If you are using Oracle Linux (or a similar distribution), you might need to load theiptables_natmodule explicitly using the command:sudo modprobe iptables_natThis step is crucial because the
iptable_natmodule is required for the Azure Monitor Agent (AMA) to function correctly.After loading the module, retry the installation of the Azure Monitor Agent (AMA) pods. Note that loading the module does not make it persistent, so you may need to repeat this step if the nodes are restarted.
Additionally, ensure that your Kubernetes DaemonSet is running in privileged mode, as this is required for Azure Monitor Container Insights. And ensure that your Kubernetes cluster nodes have sufficient resources and that there are no other underlying issues affecting the pods.
References:
- Troubleshoot extension issues for Azure Arc-enabled Kubernetes clusters
- Troubleshoot platform issues for Azure Arc-enabled Kubernetes clusters If the comment helpful, Please click Upvote it.
Thanks
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Rahul Jorrigala 3,655 Reputation points Microsoft External Staff Moderator2025-07-29T02:25:06.48+00:00 Hello Julien Taveau,
Just want to check if the above comment worked for you or else please let us know if any help, we are always here to help whenever you need us.
If the comment is helpful, please click "Upvote it"
Thankyou
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Julien Taveau 0 Reputation points
2025-07-29T09:23:44.8666667+00:00 iptable_natis already loadedlsmod | grep -i iptable iptable_mangle 16384 1 iptable_filter 16384 2 iptable_nat 16384 2 nf_nat 45056 4 ip6table_nat,xt_nat,iptable_nat,xt_MASQUERADE ip_tables 32768 6 iptable_filter,iptable_nat,iptable_mangle x_tables 45056 18 ip6table_filter,xt_conntrack,xt_statistic,iptable_filter,ip6table_nat,xt_multiport,xt_tcpudp,xt_addrtype,xt_nat,xt_comment,ip6_tables,ipt_REJECT,ip_tables,iptable_nat,ip6table_mangle,xt_MASQUERADE,iptable_mangle,xt_mark -
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Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator2025-08-05T21:25:32.36+00:00 Hello @Julien Taveau,
are you still facing the issue? required assistance on it.
If a pod has a CrashLoopBackOff status, then the pod probably failed or exited unexpectedly, and the log contains an exit code that isn't zero. Here are several possible reasons why your pod is stuck in CrashLoopBackOff mode: https://learn.microsoft.com/en-us/troubleshoot/azure/azure-kubernetes/create-upgrade-delete/pod-stuck-crashloopbackoff-mode?source=recommendations
If you have any further queries, do let us know.
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