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TCP Port Status

Collect and analyze information about the specified TCP port.


TCP Port Status Collector

To collect information about the specified TCP port on the host where the collector runs, you can use the tcpPortStatus collector. If an interface is specified in the collector, this preflight check looks up the IPv4 address of that interface, binds to it, and connects to the same address. If no interface is specified, the test server binds to 0.0.0.0 and attempts to connect to the first non-loopback IPv4 address found on a network interface on the host. Typically, no interface should be specified.

Parameters

In addition to the shared collector properties, the tcpPortStatus collector accepts the following parameters:

port (Required)

The port number to check on the host where the collector is run.

interface (Optional)

If set, the collector uses the IP address of the of the specified interface.

Example Collector Definition

apiVersion: troubleshoot.sh/v1beta2
kind: SupportBundle
metadata:
  name: tcpPortStatus
spec:
  hostCollectors:
    - tcpPortStatus:
        collectorName: kubernetes-api-tcp-port
        port: 6443
        interface: eth0

Included Resources

The results of the tcpPortStatus collector are stored in the host-collectors/tcpPortStatus directory of the support bundle.

[collector-name].json

If the collectorName field is unset, it will be named tcpPortStatus.json.

Example of the resulting file:

connected

TCP Port Status Analyzer

The tcpPortStatus analyzer supports multiple outcomes:

  • connection-refused: Connection to the port was refused.
  • connection-timeout: Timed out connecting to the port.
  • address-in-use: Specified port is unavailable.
  • connected: Successfully connected to the port.
  • error: Unexpected error connecting to the port.

Example Analyzer Definition

apiVersion: troubleshoot.sh/v1beta2
kind: SupportBundle
metadata:
  name: tcpPortStatus
spec:
  hostCollectors:
    - tcpPortStatus:
        collectorName: kubernetes-api-tcp-port
        port: 6443
        interface: eth0
  hostAnalyzers:
    - tcpPortStatus:
        checkName: "Kubernetes API TCP Port Status"
        outcomes:
          - fail:
              when: "connection-refused"
              message: Connection to port 6443 was refused. This is likely to be a routing problem since this preflight configures a test server to listen on this port.
          - warn:
              when: "address-in-use"
              message: Another process was already listening on port 6443.
          - fail:
              when: "connection-timeout"
              message: Timed out connecting to port 6443. Check your firewall.
          - fail:
              when: "error"
              message: Unexpected port status
          - pass:
              when: "connected"
              message: Port 6443 is open
          - warn:
              message: Unexpected port status
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