Antctl

Antctl is the command-line tool for Antrea. At the moment, antctl supports running in two different modes:

  • “controller mode”: when run out-of-cluster or from within the Antrea Controller Pod, antctl can connect to the Antrea Controller and query information from it (e.g. the set of computed NetworkPolicies).
  • “agent mode”: when run from within an Antrea Agent Pod, antctl can connect to the Antrea Agent and query information local to that Agent (e.g. the set of computed NetworkPolicies received by that Agent from the Antrea Controller, as opposed to the entire set of computed policies).

Table of Contents

Installation

The antctl binary is included in the Antrea Docker image (antrea/antrea-ubuntu) which means that there is no need to install anything to connect to the Antrea Agent. Simply exec into the antrea-agent container for the appropriate antrea-agent Pod and run antctl:

  1. kubectl exec -it ANTREA-AGENT_POD_NAME -n kube-system -c antrea-agent bash
  2. > antctl help

Starting with Antrea release v0.5.0, we publish the antctl binaries for different OS / CPU Architecture combinations. Head to the releases page and download the appropriate one for your machine. For example:

On Mac & Linux:

  1. curl -Lo ./antctl "https://github.com/vmware-tanzu/antrea/releases/download/<TAG>/antctl-$(uname)-x86_64"
  2. chmod +x ./antctl
  3. mv ./antctl /some-dir-in-your-PATH/antctl
  4. antctl version

For Linux, we also publish binaries for Arm-based systems.

On Windows, using PowerShell:

  1. Invoke-WebRequest -Uri https://github.com/vmware-tanzu/antrea/releases/download/<TAG>/antctl-windows-x86_64.exe -Outfile antctl.exe
  2. Move-Item .\antctl.exe c:\some-dir-in-your-PATH\antctl.exe
  3. antctl version

Usage

To see the list of available commands and options, run antctl help. The list will be different based on whether you are connecting to the Antrea Controller or Agent.

When running out-of-cluster (“controller mode” only), antctl will look for your kubeconfig file at $HOME/.kube/config by default. You can select a different one by setting the KUBECONFIG environment variable or with --kubeconfig (the latter taking precedence over the former).

The following sub-sections introduce a few commands which are useful for troubleshooting the Antrea system.

Showing or changing log verbosity level

Starting from version 0.10.0, Antrea supports showing or changing the log verbosity level of Antrea Controller or Agent using the antctl log-level command. The command can only run locally inside the antrea-controller or antrea-agent container.

The following command prints the current log verbosity level:

  1. antctl log-level

This command updates the log verbosity level (the LEVEL argument must be an integer):

  1. antctl log-level LEVEL

Collecting support information

Starting with version 0.7.0, Antrea supports the antctl supportbundle command, which can collect information from the cluster, the Antrea Controller and all Antrea agents. This information is useful when trying to troubleshoot issues in Kubernetes clusters using Antrea. In particular, when running the command out-of-cluster, all the information can be collected under one single directory, which you can upload and share when reporting issues on Github. Simply run the command as follows:

  1. antctl supportbundle [-d TARGET_DIR]

If you omit to provide a directory, antctl will create one in the current working directory, using the current timestamp as a suffix. The command also provides additional flags to filter the results: run antctl supportbundle --help for the full list.

The collected support bundle will include the following (more information may be included over time):

  • cluster information: description of the different K8s resources in the cluster (Nodes, Deployments, etc.).
  • Antrea Controller information: all the available logs (contents will vary based on the verbosity selected when running the controller) and state stored at the controller (e.g. computed NetworkPolicy objects).
  • Antrea Agent information: all the available logs from the agent and the OVS daemons, network configuration of the Node (e.g. routes, iptables rules, OVS flows) and state stored at the agent (e.g. computed NetworkPolicy objects received from the controller).

Be aware that the generated support bundle includes a lot of information, including logs, so please review the contents of the directory before sharing it on Github and ensure that you do not share anything sensitive.

The antctl supportbundle command can also be run inside a Controller or Agent Pod, in which case only local information will be collected.

controllerinfo and agentinfo commands

antctl controller command get controllerinfo (or get ci) and agent command get agentinfo (or get ai) print the runtime information of antrea-controller and antrea-agent respectively.

  1. antctl get controllerinfo
  2. antctl get agentinfo

NetworkPolicy commands

Both Antrea Controller and Agent support querying the NetworkPolicy objects in the Antrea control plane API. The source of a control plane NetworkPolicy is the original policy resource (K8s NetworkPolicy or Antrea-native Policy) from which the control plane NetworkPolicy was derived.

  • antctl get networkpolicy (or get netpol) command can print all NetworkPolicies, a specified NetworkPolicy, or NetworkPolicies in a specified Namespace.
  • get appliedtogroup (or get atg) command can print all NetworkPolicy AppliedToGroups (AppliedToGroup includes the Pods to which a NetworkPolicy is applied), or a specified AppliedToGroup.
  • get addressgroup (or get ag) command can print all NetworkPolicy AddressGroups (AddressGroup defines source or destination addresses of NetworkPolicy rules), or a specified AddressGroup.

Using the json or yaml antctl output format can print more information of NetworkPolicy, AppliedToGroup, and AddressGroup, than using the default table output format. The NAME of a control plane NetworkPolicy is the UID of its source NetworkPolicy.

  1. antctl get networkpolicy [NAME] [-n NAMESPACE] [-o yaml]
  2. antctl get appliedtogroup [NAME] [-o yaml]
  3. antctl get addressgroup [NAME] [-o yaml]

NetworkPolicy also supports sort-by=effectivePriority option, which can be used to view the effective order in which the NetworkPolicies are evaluated. Antrea-native NetworkPolicy ordering is documented here.

  1. antctl get networkpolicy --sort-by=effectivePriority

Antrea Agent supports some extra antctl commands.

  • Printing NetworkPolicies applied to a specific local Pod.

    1. antctl get networkpolicy -p POD -n NAMESPACE

  • Printing NetworkPolicies with a specific source NetworkPolicy type.

    1. antctl get networkpolicy -T (K8sNP|ACNP|ANP)

  • Printing NetworkPolicies with a specific source NetworkPolicy name.

    1. antctl get networkpolicy -S SOURCE_NAME [-n NAMESPACE]

Mapping endpoints to NetworkPolicies

antctl supports mapping a specific Pod to the NetworkPolicies which “select” this Pod, either because they apply to the Pod directly or because one of their policy rules selects the Pod.

  1. antctl query endpoint -p POD [-n NAMESPACE]

If no Namespace is provided with -n, the command will default to the “default” Namespace.

This command only works in “controller mode” and as of now it can only be run from inside the Antrea Controller Pod, and not from out-of-cluster.

Dumping Pod network interface information

antctl agent command get podinterface (or get pi) can dump network interface information of all local Pods, or a specified local Pod, or local Pods in the specified Namespace, or local Pods matching the specified Pod name.

  1. antctl get podinterface [NAME] [-n NAMESPACE]

Dumping OVS flows

Starting from version 0.6.0, Antrea Agent supports dumping Antrea OVS flows. The antctl get ovsflows (or get of) command can dump all OVS flows, flows added for a specified Pod, or flows added for Service load-balancing of a specified Service, or flows added to realize a specified NetworkPolicy, or flows in a specified OVS flow table.

  1. antctl get ovsflows
  2. antctl get ovsflows -p POD -n NAMESPACE
  3. antctl get ovsflows -S SERVICE -n NAMESPACE
  4. antctl get ovsflows -N NETWORKPOLICY -n NAMESPACE
  5. antctl get ovsflows -T TABLE_A,TABLE_B
  6. antctl get ovsflows -T TABLE_A,TABLE_B_NUM
  7. antctl get ovsflows -T TABLE_A_NUM,TABLE_B_NUM

OVS flow tables can be specified using table names, or the table numbers. antctl get ovsflow --help lists all Antrea flow tables. For more information about Antrea OVS pipeline and flows, please refer to the OVS pipeline doc.

Example outputs of dumping Pod and NetworkPolicy OVS flows:

  1. # Dump OVS flows of Pod "coredns-6955765f44-zcbwj"
  2. $ antctl get of -p coredns-6955765f44-zcbwj -n kube-system
  3. FLOW
  4. table=classification, n_packets=513122, n_bytes=42615080, priority=190,in_port="coredns--d0c58e" actions=load:0x2->NXM_NX_REG0[0..15],resubmit(,10)
  5. table=10, n_packets=513122, n_bytes=42615080, priority=200,ip,in_port="coredns--d0c58e",dl_src=52:bd:c6:e0:eb:c1,nw_src=172.100.1.7 actions=resubmit(,30)
  6. table=10, n_packets=0, n_bytes=0, priority=200,arp,in_port="coredns--d0c58e",arp_spa=172.100.1.7,arp_sha=52:bd:c6:e0:eb:c1 actions=resubmit(,20)
  7. table=80, n_packets=556468, n_bytes=166477824, priority=200,dl_dst=52:bd:c6:e0:eb:c1 actions=load:0x5->NXM_NX_REG1[],load:0x1->NXM_NX_REG0[16],resubmit(,90)
  8. table=70, n_packets=0, n_bytes=0, priority=200,ip,dl_dst=aa:bb:cc:dd:ee:ff,nw_dst=172.100.1.7 actions=set_field:62:39:b4:e8:05:76->eth_src,set_field:52:bd:c6:e0:eb:c1->eth_dst,dec_ttl,resubmit(,80)
  10. # Get NetworkPolicies applied to Pod "coredns-6955765f44-zcbwj"
  11. $ antctl get netpol -p coredns-6955765f44-zcbwj -n kube-system
  12. NAMESPACE   NAME     APPLIED-TO                           RULES
  13. kube-system kube-dns 160ea6d7-0234-5d1d-8ea0-b703d0aa3b46 1
  15. # Dump OVS flows of NetworkPolicy "kube-dns"
  16. $ antctl get of -N kube-dns -n kube-system
  17. FLOW
  18. table=90, n_packets=0, n_bytes=0, priority=190,conj_id=1,ip actions=resubmit(,105)
  19. table=90, n_packets=0, n_bytes=0, priority=200,ip actions=conjunction(1,1/3)
  20. table=90, n_packets=0, n_bytes=0, priority=200,ip,reg1=0x5 actions=conjunction(2,2/3),conjunction(1,2/3)
  21. table=90, n_packets=0, n_bytes=0, priority=200,udp,tp_dst=53 actions=conjunction(1,3/3)
  22. table=90, n_packets=0, n_bytes=0, priority=200,tcp,tp_dst=53 actions=conjunction(1,3/3)
  23. table=90, n_packets=0, n_bytes=0, priority=200,tcp,tp_dst=9153 actions=conjunction(1,3/3)
  24. table=100, n_packets=0, n_bytes=0, priority=200,ip,reg1=0x5 actions=drop

OVS packet tracing

Starting from version 0.7.0, Antrea Agent supports tracing the OVS flows that a specified packet traverses, leveraging the OVS packet tracing tool.

antctl trace-packet command starts a packet tracing operation. antctl help trace-packet shows the usage of the command. This section lists a few trace-packet command examples.

  1. # Trace an IP packet between two Pods
  2. antctl trace-packet -S ns1/pod1 -D ns2/pod2
  3. # Trace a Service request from a local Pod
  4. antctl trace-packet -S ns1/pod1 -D ns2/svc2 -f "tcp,tcp_dst=80"
  5. # Trace the Service reply packet (assuming "ns2/pod2" is the Service backend Pod)
  6. antctl trace-packet -D ns1/pod1 -S ns2/pod2 -f "tcp,tcp_src=80"
  7. # Trace an IP packet from a Pod to gateway port
  8. antctl trace-packet -S ns1/pod1 -D antrea-gw0
  9. # Trace a UDP packet from a Pod to an IP address
  10. antctl trace-packet -S ns1/pod1 -D 10.1.2.3 -f udp,udp_dst=1234
  11. # Trace a UDP packet from an IP address to a Pod
  12. antctl trace-packet -D ns1/pod1 -S 10.1.2.3 -f udp,udp_src=1234
  13. # Trace an ARP request from a local Pod
  14. antctl trace-packet -p ns1/pod1 -f arp,arp_spa=10.1.2.3,arp_sha=00:11:22:33:44:55,arp_tpa=10.1.2.1,dl_dst=ff:ff:ff:ff:ff:ff

Example outputs of tracing a UDP (DNS request) packet from a remote Pod to a local (coredns) Pod:

  1. $ antctl trace-packet -S default/web-client -D kube-system/coredns-6955765f44-zcbwj -f udp,udp_dst=53
  2. result: |
  3.   Flow: udp,in_port=1,vlan_tci=0x0000,dl_src=aa:bb:cc:dd:ee:ff,dl_dst=aa:bb:cc:dd:ee:ff,nw_src=172.100.2.11,nw_dst=172.100.1.7,nw_tos=0,nw_ecn=0,nw_ttl=64,tp_src=0,tp_dst=53
  5.   bridge("br-int")
  6.   ----------------
  7.    0. in_port=1, priority 200, cookie 0x5e000000000000
  8.       load:0->NXM_NX_REG0[0..15]
  9.       resubmit(,30)
  10.   30. ip, priority 200, cookie 0x5e000000000000
  11.       ct(table=31,zone=65520)
  12.       drop
  13.        -> A clone of the packet is forked to recirculate. The forked pipeline will be resumed at table 31.
  14.        -> Sets the packet to an untracked state, and clears all the conntrack fields.
  16.   Final flow: unchanged
  17.   Megaflow: recirc_id=0,eth,udp,in_port=1,nw_frag=no,tp_src=0x0/0xfc00
  18.   Datapath actions: ct(zone=65520),recirc(0x53)
  20.   ===============================================================================
  21.   recirc(0x53) - resume conntrack with default ct_state=trk|new (use --ct-next to customize)
  22.   ===============================================================================
  24.   Flow: recirc_id=0x53,ct_state=new|trk,ct_zone=65520,eth,udp,in_port=1,vlan_tci=0x0000,dl_src=aa:bb:cc:dd:ee:ff,dl_dst=aa:bb:cc:dd:ee:ff,nw_src=172.100.2.11,nw_dst=172.100.1.7,nw_tos=0,nw_ecn=0,nw_ttl=64,tp_src=0,tp_dst=53
  26.   bridge("br-int")
  27.   ----------------
  28.       thaw
  29.           Resuming from table 31
  30.   31. priority 0, cookie 0x5e000000000000
  31.       resubmit(,40)
  32.   40. priority 0, cookie 0x5e000000000000
  33.       resubmit(,50)
  34.   50. priority 0, cookie 0x5e000000000000
  35.       resubmit(,60)
  36.   60. priority 0, cookie 0x5e000000000000
  37.       resubmit(,70)
  38.   70. ip,dl_dst=aa:bb:cc:dd:ee:ff,nw_dst=172.100.1.7, priority 200, cookie 0x5e030000000000
  39.       set_field:62:39:b4:e8:05:76->eth_src
  40.       set_field:52:bd:c6:e0:eb:c1->eth_dst
  41.       dec_ttl
  42.       resubmit(,80)
  43.   80. dl_dst=52:bd:c6:e0:eb:c1, priority 200, cookie 0x5e030000000000
  44.       load:0x5->NXM_NX_REG1[]
  45.       load:0x1->NXM_NX_REG0[16]
  46.       resubmit(,90)
  47.   90. conj_id=2,ip, priority 190, cookie 0x5e050000000000
  48.       resubmit(,105)
  49.   105. ct_state=+new+trk,ip, priority 190, cookie 0x5e000000000000
  50.       ct(commit,table=110,zone=65520)
  51.       drop
  52.        -> A clone of the packet is forked to recirculate. The forked pipeline will be resumed at table 110.
  53.        -> Sets the packet to an untracked state, and clears all the conntrack fields.
  55.   Final flow: recirc_id=0x53,eth,udp,reg0=0x10000,reg1=0x5,in_port=1,vlan_tci=0x0000,dl_src=62:39:b4:e8:05:76,dl_dst=52:bd:c6:e0:eb:c1,nw_src=172.100.2.11,nw_dst=172.100.1.7,nw_tos=0,nw_ecn=0,nw_ttl=63,tp_src=0,tp_dst=53
  56.   Megaflow: recirc_id=0x53,ct_state=+new-est-inv+trk,ct_mark=0,eth,udp,in_port=1,dl_src=aa:bb:cc:dd:ee:ff,dl_dst=aa:bb:cc:dd:ee:ff,nw_src=192.0.0.0/2,nw_dst=172.100.1.7,nw_ttl=64,nw_frag=no,tp_dst=53
  57.   Datapath actions: set(eth(src=62:39:b4:e8:05:76,dst=52:bd:c6:e0:eb:c1)),set(ipv4(ttl=63)),ct(commit,zone=65520),recirc(0x54)
  59.   ===============================================================================
  60.   recirc(0x54) - resume conntrack with default ct_state=trk|new (use --ct-next to customize)
  61.   ===============================================================================
  63.   Flow: recirc_id=0x54,ct_state=new|trk,ct_zone=65520,eth,udp,reg0=0x10000,reg1=0x5,in_port=1,vlan_tci=0x0000,dl_src=62:39:b4:e8:05:76,dl_dst=52:bd:c6:e0:eb:c1,nw_src=172.100.2.11,nw_dst=172.100.1.7,nw_tos=0,nw_ecn=0,nw_ttl=63,tp_src=0,tp_dst=53
  65.   bridge("br-int")
  66.   ----------------
  67.       thaw
  68.           Resuming from table 110
  69.   110. ip,reg0=0x10000/0x10000, priority 200, cookie 0x5e000000000000
  70.       output:NXM_NX_REG1[]
  71.        -> output port is 5
  73.   Final flow: unchanged
  74.   Megaflow: recirc_id=0x54,eth,ip,in_port=1,nw_frag=no
  75.   Datapath actions: 3

Traceflow

antctl traceflow command is used to start a traceflow and retrieve its result. After the result is collected, the traceflow will be deleted. Users can also create a traceflow with kubectl, but antctl traceflow offers a simpler approach.

The required options for this command are source and destination, which consist of Namespace and Pod, Service or IP. The command supports yaml and json output. If users want a non blocking operation, an option: --wait=false can be added to start the traceflow without waiting for result. Then, the deletion operation will not be conducted. Besides, users can specify header protocol (ICMP, TCP and UDP), source/destination ports and TCP flags, and can specify if it’s IPv6 or not as well.

For example:

  1. $ antctl traceflow -S busybox0 -D busybox1
  2. name: default-busybox0-to-default-busybox1-fpllngzi
  3. phase: Succeeded
  4. source: default/busybox0
  5. destination: default/busybox1
  6. results:
  7. - node: antrea-linux-testbed7-1
  8.   timestamp: 1596435607
  9.   observations:
  10.   - component: SpoofGuard
  11.     action: Forwarded
  12.   - component: Forwarding
  13.     componentInfo: Output
  14.     action: Delivered

Antctl Proxy

Antctl can run as a reverse proxy for the Antrea API (Controller or arbitrary Agent). Usage is very similar to kubectl proxy and the implementation is essentially the same.

To run a reverse proxy for the Antrea Controller API, use:

  1. antctl proxy --controller

To run a reverse proxy for the Antrea Agent API for the antrea-agent Pod running on Node <TARGET_NODE>, use:

  1. antctl proxy --agent-node

You can then access the API at 127.0.0.1:8001. To implement this functionality, antctl retrieves the Node IP address and API server port for the Antrea Controller or for the specified Agent from the K8s API, and it proxies all the requests received on 127.0.0.1:8001 directly to that IP / port. One thing to keep in mind is that the TLS connection between the proxy and the Antrea Agent or Controller will not be secure (no certificate verification), and the proxy should be used for debugging only.

To see the full list of supported options, run antctl proxy --help.

This feature is useful if one wants to use the Go pprof tool to collect runtime profiling data about the Antrea components. Please refer to this document for more information.