Troubleshooting

This document describes how to troubleshoot Cilium in different deployment modes. It focuses on a full deployment of Cilium within a datacenter or public cloud. If you are just looking for a simple way to experiment, we highly recommend trying out the Getting Started Guides instead.

This guide assumes that you have read the Concepts which explains all the components and concepts.

We use GitHub issues to maintain a list of Cilium Frequently Asked Questions (FAQ). You can also check there to see if your question(s) is already addressed.

Component & Cluster Health

Kubernetes

An initial overview of Cilium can be retrieved by listing all pods to verify whether all pods have the status Running:

$ kubectl -n kube-system get pods -l k8s-app=cilium
NAME           READY     STATUS    RESTARTS   AGE
cilium-2hq5z   1/1       Running   0          4d
cilium-6kbtz   1/1       Running   0          4d
cilium-klj4b   1/1       Running   0          4d
cilium-zmjj9   1/1       Running   0          4d

If Cilium encounters a problem that it cannot recover from, it will automatically report the failure state via cilium status which is regularly queried by the Kubernetes liveness probe to automatically restart Cilium pods. If a Cilium pod is in state CrashLoopBackoff then this indicates a permanent failure scenario.

Detailed Status

If a particular Cilium pod is not in running state, the status and health of the agent on that node can be retrieved by running cilium status in the context of that pod:

$ kubectl -n kube-system exec -ti cilium-2hq5z -- cilium status
KVStore:                Ok   etcd: 1/1 connected: http://demo-etcd-lab--a.etcd.tgraf.test1.lab.corp.covalent.link:2379 - 3.2.5 (Leader)
ContainerRuntime:       Ok   docker daemon: OK
Kubernetes:             Ok   OK
Kubernetes APIs:        ["cilium/v2::CiliumNetworkPolicy", "networking.k8s.io/v1::NetworkPolicy", "core/v1::Service", "core/v1::Endpoint", "core/v1::Node", "CustomResourceDefinition"]
Cilium:                 Ok   OK
NodeMonitor:            Disabled
Cilium health daemon:   Ok
Controller Status:      14/14 healthy
Proxy Status:           OK, ip 10.2.0.172, port-range 10000-20000
Cluster health:   4/4 reachable   (2018-06-16T09:49:58Z)

Alternatively, the k8s-cilium-exec.sh script can be used to run cilium status on all nodes. This will provide detailed status and health information of all nodes in the cluster:

$ curl -sLO releases.cilium.io/v1.1.0/tools/k8s-cilium-exec.sh
$ chmod +x ./k8s-cilium-exec.sh

… and run cilium status on all nodes:

$ ./k8s-cilium-exec.sh cilium status
KVStore:                Ok   Etcd: http://127.0.0.1:2379 - (Leader) 3.1.10
ContainerRuntime:       Ok
Kubernetes:             Ok   OK
Kubernetes APIs:        ["extensions/v1beta1::Ingress", "core/v1::Node", "CustomResourceDefinition", "cilium/v2::CiliumNetworkPolicy", "networking.k8s.io/v1::NetworkPolicy", "core/v1::Service", "core/v1::Endpoint"]
Cilium:                 Ok   OK
NodeMonitor:            Listening for events on 2 CPUs with 64x4096 of shared memory
Cilium health daemon:   Ok
Controller Status:      7/7 healthy
Proxy Status:           OK, ip 10.15.28.238, 0 redirects, port-range 10000-20000
Cluster health:   1/1 reachable   (2018-02-27T00:24:34Z)

Logs

To retrieve log files of a cilium pod, run (replace cilium-1234 with a pod name returned by kubectl -n kube-system get pods -l k8s-app=cilium)

$ kubectl -n kube-system logs --timestamps cilium-1234

If the cilium pod was already restarted due to the liveness problem after encountering an issue, it can be useful to retrieve the logs of the pod before the last restart:

$ kubectl -n kube-system logs --timestamps -p cilium-1234

Generic

When logged in a host running Cilium, the cilium CLI can be invoked directly, e.g.:

$ cilium status
KVStore:                Ok   etcd: 1/1 connected: https://192.168.33.11:2379 - 3.2.7 (Leader)
ContainerRuntime:       Ok
Kubernetes:             Ok   OK
Kubernetes APIs:        ["core/v1::Endpoint", "extensions/v1beta1::Ingress", "core/v1::Node", "CustomResourceDefinition", "cilium/v2::CiliumNetworkPolicy", "networking.k8s.io/v1::NetworkPolicy", "core/v1::Service"]
Cilium:                 Ok   OK
NodeMonitor:            Listening for events on 2 CPUs with 64x4096 of shared memory
Cilium health daemon:   Ok
IPv4 address pool:      261/65535 allocated
IPv6 address pool:      4/4294967295 allocated
Controller Status:      20/20 healthy
Proxy Status:           OK, ip 10.0.28.238, port-range 10000-20000
Cluster health:   2/2 reachable   (2018-04-11T15:41:01Z)

Connectivity Problems

Checking cluster connectivity health

Cilium allows to rule out network fabric related issues when troubleshooting connectivity issues by providing reliable health and latency probes between all cluster nodes and between a simulated workload running on each node.

By default when Cilium is run, it launches instances of cilium-health in the background to determine overall connectivity status of the cluster. This tool periodically runs bidirectional traffic across multiple paths through the cluster and through each node using different protocols to determine the health status of each path and protocol. At any point in time, cilium-health may be queried for the connectivity status of the last probe.

$ kubectl -n kube-system exec -ti cilium-2hq5z -- cilium-health status
Probe time:   2018-06-16T09:51:58Z
Nodes:
  ip-172-0-52-116.us-west-2.compute.internal (localhost):
    Host connectivity to 172.0.52.116:
      ICMP to stack: OK, RTT=315.254µs
      HTTP to agent: OK, RTT=368.579µs
    Endpoint connectivity to 10.2.0.183:
      ICMP to stack: OK, RTT=190.658µs
      HTTP to agent: OK, RTT=536.665µs
  ip-172-0-117-198.us-west-2.compute.internal:
    Host connectivity to 172.0.117.198:
      ICMP to stack: OK, RTT=1.009679ms
      HTTP to agent: OK, RTT=1.808628ms
    Endpoint connectivity to 10.2.1.234:
      ICMP to stack: OK, RTT=1.016365ms
      HTTP to agent: OK, RTT=2.29877ms

For each node, the connectivity will be displayed for each protocol and path, both to the node itself and to an endpoint on that node. The latency specified is a snapshot at the last time a probe was run, which is typically once per minute. The ICMP connectivity row represents Layer 3 connectivity to the networking stack, while the HTTP connectivity row represents connection to an instance of the cilium-health agent running on the host or as an endpoint.

Monitoring Packet Drops

Sometimes you may experience broken connectivity, which may be due to a number of different causes. A main cause can be unwanted packet drops on the networking level. The tool cilium monitor allows you to quickly inspect and see if and where packet drops happen. Following is an example output (use kubectl exec as in previous examples if running with Kubernetes):

$ kubectl -n kube-system exec -ti cilium-2hq5z -- cilium monitor --type drop
Listening for events on 2 CPUs with 64x4096 of shared memory
Press Ctrl-C to quit
xx drop (Policy denied (L3)) to endpoint 25729, identity 261->264: fd02::c0a8:210b:0:bf00 -> fd02::c0a8:210b:0:6481 EchoRequest
xx drop (Policy denied (L3)) to endpoint 25729, identity 261->264: fd02::c0a8:210b:0:bf00 -> fd02::c0a8:210b:0:6481 EchoRequest
xx drop (Policy denied (L3)) to endpoint 25729, identity 261->264: 10.11.13.37 -> 10.11.101.61 EchoRequest
xx drop (Policy denied (L3)) to endpoint 25729, identity 261->264: 10.11.13.37 -> 10.11.101.61 EchoRequest
xx drop (Invalid destination mac) to endpoint 0, identity 0->0: fe80::5c25:ddff:fe8e:78d8 -> ff02::2 RouterSolicitation

The above indicates that a packet to endpoint ID 25729 has been dropped due to violation of the Layer 3 policy.

Policy Troubleshooting

Ensure pod is managed by Cilium

A potential cause for policy enforcement not functioning as expected is that the networking of the pod selected by the policy is not being managed by Cilium. The following situations result in unmanaged pods:

  • The pod is running in host networking and will use the host’s IP address directly. Such pods have full network connectivity but Cilium will not provide security policy enforcement for such pods.
  • The pod was started before Cilium was deployed. Cilium only manages pods that have been deployed after Cilium itself was started. Cilium will not provide security policy enforcement for such pods.

If pod networking is not managed by Cilium. Ingress and egress policy rules selecting the respective pods will not be applied. See the section Network Policy for more details.

You can run the following script to list the pods which are not managed by Cilium:

$ ./contrib/k8s/k8s-unmanaged.sh
kube-system/cilium-hqpk7
kube-system/kube-addon-manager-minikube
kube-system/kube-dns-54cccfbdf8-zmv2c
kube-system/kubernetes-dashboard-77d8b98585-g52k5
kube-system/storage-provisioner

See section Troubleshooting for details and examples on how to use the policy tracing feature.

Automatic Diagnosis

The cluster-diagnosis tool can help identify the most commonly encountered issues in Cilium deployments. The tool currently supports Kubernetes and Minikube clusters only.

The tool performs various checks and provides hints to fix specific issues that it has identified.

The following is a list of prerequisites:

  • Requires Python >= 2.7.*
  • Requires kubectl.
  • kubectl should be pointing to your cluster before running the tool.

You can download the latest version of the cluster-diagnosis.zip file using the following command:

curl -sLO releases.cilium.io/tools/cluster-diagnosis.zip

Command to run the cluster-diagnosis tool:

python cluster-diagnosis.zip

Command to collect the system dump using the cluster-diagnosis tool:

python cluster-diagnosis.zip sysdump

Symptom Library

Node to node traffic is being dropped

Symptom

Endpoint to endpoint communication on a single node succeeds but communication fails between endpoints across multiple nodes.

Troubleshooting steps:

  1. Run cilium-health status on the node of the source and destination endpoint. It should describe the connectivity from that node to other nodes in the cluster, and to a simulated endpoint on each other node. Identify points in the cluster that cannot talk to each other. If the command does not describe the status of the other node, there may be an issue with the KV-Store.
  2. Run cilium monitor on the node of the source and destination endpoint. Look for packet drops.

When running in Overlay Network Mode mode:

  1. Run cilium bpf tunnel list and verify that each Cilium node is aware of the other nodes in the cluster. If not, check the logfile for errors.

  2. If nodes are being populated correctly, run tcpdump -n -i cilium_vxlan on each node to verify whether cross node traffic is being forwarded correctly between nodes.

    If packets are being dropped,

    • verify that the node IP listed in cilium bpf tunnel list can reach each other.
    • verify that the firewall on each node allows UDP port 8472.

When running in Direct / Native Routing Mode mode:

  1. Run ip route or check your cloud provider router and verify that you have routes installed to route the endpoint prefix between all nodes.
  2. Verify that the firewall on each node permits to route the endpoint IPs.

Useful Scripts

Retrieve Cilium pod managing a particular pod

Identifies the Cilium pod that is managing a particular pod in a namespace:

k8s-get-cilium-pod.sh <pod> <namespace>

Example:

$ curl -sLO releases.cilium.io/v1.1.0/tools/k8s-get-cilium-pod.sh
$ ./k8s-get-cilium-pod.sh luke-pod default
cilium-zmjj9

Execute a command in all Kubernetes Cilium pods

Run a command within all Cilium pods of a cluster

k8s-cilium-exec.sh <command>

Example:

$ curl -sLO releases.cilium.io/v1.1.0/tools/k8s-cilium-exec.sh
$ ./k8s-cilium-exec.sh uptime
 10:15:16 up 6 days,  7:37,  0 users,  load average: 0.00, 0.02, 0.00
 10:15:16 up 6 days,  7:32,  0 users,  load average: 0.00, 0.03, 0.04
 10:15:16 up 6 days,  7:30,  0 users,  load average: 0.75, 0.27, 0.15
 10:15:16 up 6 days,  7:28,  0 users,  load average: 0.14, 0.04, 0.01

List unmanaged Kubernetes pods

Lists all Kubernetes pods in the cluster for which Cilium does not provide networking. This includes pods running in host-networking mode and pods that were started before Cilium was deployed.

k8s-unmanaged.sh

Example:

$ curl -sLO releases.cilium.io/v1.1.0/tools/k8s-unmanaged.sh
$ ./k8s-unmanaged.sh
kube-system/cilium-hqpk7
kube-system/kube-addon-manager-minikube
kube-system/kube-dns-54cccfbdf8-zmv2c
kube-system/kubernetes-dashboard-77d8b98585-g52k5
kube-system/storage-provisioner

Reporting a problem

Automatic log & state collection

Before you report a problem, make sure to retrieve the necessary information from your cluster before the failure state is lost. Cilium provides a script to automatically grab logs and retrieve debug information from all Cilium pods in the cluster.

The script has the following list of prerequisites:

  • Requires Python >= 2.7.*
  • Requires kubectl.
  • kubectl should be pointing to your cluster before running the tool.

You can download the latest version of the cluster-diagnosis.zip file using the following command:

$ curl -sLO releases.cilium.io/tools/cluster-diagnosis.zip
$ python cluster-diagnosis.zip sysdump

Single Node Bugtool

If you are not running Kubernetes, it is also possible to run the bug collection tool manually with the scope of a single node:

The cilium-bugtool captures potentially useful information about your environment for debugging. The tool is meant to be used for debugging a single Cilium agent node. In the Kubernetes case, if you have multiple Cilium pods, the tool can retrieve debugging information from all of them. The tool works by archiving a collection of command output and files from several places. By default, it writes to the tmp directory.

Note that the command needs to be run from inside the Cilium pod/container.

$ cilium-bugtool

When running it with no option as shown above, it will try to copy various files and execute some commands. If kubectl is detected, it will search for Cilium pods. The default label being k8s-app=cilium, but this and the namespace can be changed via k8s-namespace and k8s-label respectively.

If you’d prefer to browse the dump, there is a HTTP flag.

$ cilium-bugtool --serve

If you want to capture the archive from a Kubernetes pod, then the process is a bit different

# First we need to get the Cilium pod
$ kubectl get pods --namespace kube-system
  NAME                          READY     STATUS    RESTARTS   AGE
  cilium-kg8lv                  1/1       Running   0          13m
  kube-addon-manager-minikube   1/1       Running   0          1h
  kube-dns-6fc954457d-sf2nk     3/3       Running   0          1h
  kubernetes-dashboard-6xvc7    1/1       Running   0          1h

# Run the bugtool from this pod
$ kubectl -n kube-system exec cilium-kg8lv cilium-bugtool
  [...]

# Copy the archive from the pod
$ kubectl cp kube-system/cilium-kg8lv:/tmp/cilium-bugtool-20180411-155146.166+0000-UTC-266836983.tar /tmp/cilium-bugtool-20180411-155146.166+0000-UTC-266836983.tar
  [...]

Note

Please check the archive for sensitive information and strip it away before sharing it with us.

Below is an approximate list of the kind of information in the archive.

  • Cilium status
  • Cilium version
  • Kernel configuration
  • Resolve configuration
  • Cilium endpoint state
  • Cilium logs
  • Docker logs
  • dmesg
  • ethtool
  • ip a
  • ip link
  • ip r
  • iptables-save
  • kubectl -n kube-system get pods
  • kubectl get pods,svc for all namespaces
  • uname
  • uptime
  • cilium bpf * list
  • cilium endpoint get for each endpoint
  • cilium endpoint list
  • hostname
  • cilium policy get
  • cilium service list

Debugging information

If you are not running Kubernetes, you can use the cilium debuginfo command to retrieve useful debugging information. If you are running Kubernetes, this command is automatically run as part of the system dump.

cilium debuginfo can print useful output from the Cilium API. The output format is in Markdown format so this can be used when reporting a bug on the issue tracker. Running without arguments will print to standard output, but you can also redirect to a file like

$ cilium debuginfo -f debuginfo.md

Note

Please check the debuginfo file for sensitive information and strip it away before sharing it with us.

Slack Assistance

The Cilium slack community is helpful first point of assistance to get help troubleshooting a problem or to discuss options on how to address a problem.

The slack community is open to everyone. You can request an invite email by visiting Slack.

Report an issue via GitHub

If you believe to have found an issue in Cilium, please report a GitHub issue and make sure to attach a system dump as described above to ensure that developers have the best chance to reproduce the issue.