View Source KubeProbex (Kube Probex v1.0.1)
Kube Probex is a lightweight and flexible Elixir library designed to help define HTTP probes in Kubernetes for applications built using the Phoenix framework. It leverages Phoenix Plug to integrate seamlessly into your web application, making it easy to ensure that your services remain healthy and responsive in Kubernetes environments.
Features
- Simple Integration: Add liveness, readiness, and startup probes to your Phoenix app with minimal configuration.
- Customizable Checks: Define your own liveness, readiness, and startup probes logic to suit your application's needs.
- Kubernetes-Ready: Built with Kubernetes probe endpoints in mind.
- Lightweight: Minimal dependencies and easy to use.
Installation
Add kube_probex
to your dependencies in mix.exs
:
def deps do
[
{:kube_probex, "~> 1.0.0"}
]
end
Then, fetch the dependencies:
mix deps.get
Usage
Adding the Plugs to Your Phoenix Endpoint or Router
To use kube_probex
, add it to your Phoenix endpoint or router as a plug:
Liveness
# lib/my_app_web/endpoint.ex
defmodule MyAppWeb.Endpoint do
use Phoenix.Endpoint, otp_app: :my_app_web
plug KubeProbex.Plug.Liveness, path: ~w(/_health /_healthz)
end
This will expose:
- A liveness probe endpoint at
/_health
and/_healthz
paths.
Readiness
# lib/my_app_web/endpoint.ex
defmodule MyAppWeb.Endpoint do
use Phoenix.Endpoint, otp_app: :my_app_web
plug KubeProbex.Plug.Readiness, path: ~w(/_ready /_readyz), otp_apps: [:my_app]
end
This will expose:
- A readiness probe endpoint at
/_ready
and/_readyz
paths.
Note
Check the Available Plugs section in the sidebar for a list of all available plugs.
Customizing Probe Checks
You can define custom probe checks by configuring kube_probex
. Add a module implementing one of the
check behaviours:
defmodule MyApp.LivenessCheck do
@behaviour KubeProbex.Check.Liveness
alias Plug.Conn
@impl true
def check(conn, _liveness_plug_opts) do
if some_condition() do
conn
|> Conn.put_resp_content_type("application/json")
|> Conn.send_resp(200, ~s({"status": "ok"}))
else
conn
|> Conn.put_resp_content_type("application/json")
|> Conn.send_resp(500, ~s({"status": "error"}))
end
end
defp some_condition do
# Your custom logic here
true
end
end
Then, configure kube_probex
to use your custom check in config/config.exs
:
config :kube_probex, liveness_check: MyApp.LivenessCheck
Kubernetes Configuration
In your Kubernetes deployment manifest, configure the liveness probe to point to the exposed endpoint:
livenessProbe:
httpGet:
path: /_health
port: 4000
initialDelaySeconds: 5
periodSeconds: 10
Note
Check the Behaviours section in the sidebar for a list of all behaviours.