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inspecting-consul-agent

Inspecting Local Consul Agent Logs​

When running a local Consul Agent (e.g., via consul agent -dev -config-file test_config.json), logs appear directly in the same terminal window or console. These logs provide real-time insights into the agent's operations, including service registrations, health checks, and any errors or warnings.

An example of your startup log would look like this:

==> Starting Consul agent...
        Version: '1.14.0'
        Node ID: 'a1b2c3d4-e5f6-7890-abcd-ef1234567890'
        Node name: 'your-machine-name'
        Datacenter: 'dc1' (Segment: '<all>')
        Server: true (Bootstrap: true)
        Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, gRPC: 8502, gRPC-TLS: 8503, DNS: 8600)
        Cluster Addr: 127.0.0.1 (LAN: 8301, WAN: 8302)
        Gossip Encryption: true
        Auto-Encrypt-TLS: false
        ACL Enabled: true
        Reporting Enabled: false
        ACL Default Policy: allow
        HTTPS TLS: Verify Incoming: false, Verify Outgoing: false, Min Version: TLSv1_2
        gRPC TLS: Verify Incoming: false, Min Version: TLSv1_2
        Internal RPC TLS: Verify Incoming: false, Verify Outgoing: false (Verify Hostname: false), Min Version: TLSv1_2
==> Log data will now stream in as it occurs:

These logs show real-time events like node joins, service registrations, and key/value updates. Keep this console open while testing your contribution...it’s your real-time feedback loop.

Inspecting Local Agent State via Web UI​

When Consul runs in dev mode, it automatically serves a Web UI that lets you visualize the cluster’s current state which can be accessed via your browser at http://127.0.0.1:8500/ui.

Here, you can explore components of your cluster, such as:

  • Services: View registered services, their health status, and metadata.
  • Nodes: See all nodes in the cluster, their status, and associated services.
  • Key/Value: Inspect and manage key/value pairs stored in Consul.
  • Intentions: Manage communication permissions between services.
  • Tokens: View and manage ACL tokens used for authentication and authorization.
  • Policies: Manage ACL policies that define access rules. etc.

Useful Tip: Use the Web UI to verify that your tests register/deregister services correctly or modify expected state. It’s also a great place to debug unexpected behavior before submitting a PR.