`vector validate` emits error `TCP bind failed: Address already in use (os error 98)` when doing systemd reload #22916

techministrator · 2025-04-21T11:00:56Z

techministrator
Apr 21, 2025

Hi Vector maintainers,

I see that the command vector validate has problem with the case of reloading.

I'm using Vector version 0.44.0.

This is the systemd default configurations for vector.service on Ubuntu 22.04.

# /lib/systemd/system/vector.service
[Unit]
Description=Vector
Documentation=https://vector.dev
After=network-online.target
Requires=network-online.target

[Service]
User=vector
Group=vector
ExecStartPre=/usr/bin/vector validate
ExecStart=/usr/bin/vector
ExecReload=/usr/bin/vector validate
ExecReload=/bin/kill -HUP $MAINPID
Restart=always
AmbientCapabilities=CAP_NET_BIND_SERVICE
EnvironmentFile=-/etc/default/vector
# Since systemd 229, should be in [Unit] but in order to support systemd <229,
# it is also supported to have it here.
StartLimitInterval=10
StartLimitBurst=5
[Install]
WantedBy=multi-user.target

Here is the simple vector config file with datadog agents

sources:
  datadog_agents:
    type: datadog_agent
    address: 0.0.0.0:9000
    disable_logs: true
    disable_traces: true
    store_api_key: true

sinks:
  datadog_platform:
    inputs:
      - datadog_agents
    type: datadog_metrics

With that config, the running process of vector already takes the port 9000. So when running vector validate, it would always result in this error because obviously the port is still being used by the current vector process:

$ vector validate
2025-04-21T10:57:33.627587Z  INFO vector::app: Log level is enabled. level="INFO"
√ Loaded ["/etc/vector/vector.yaml"]

Component errors
----------------
x Source "datadog_agents": TCP bind failed: Address already in use (os error 98)

I can totally just run the kill -HUP <pid> but I think it would be better if the vector validate is able to handle such above case.