Block until ready

The blocking strategy holds the incoming request until your instances are ready, then forwards it.

--strategy.blocking.default-timeout

There is no waiting page; the client waits for the response. This is the right choice for APIs and any client that expects to wait for a reply rather than see an HTML loading page.

    flowchart LR
    request[Request arrives] --> hold[Request held open]
    hold -->|instance ready| forward[Forward the request]
    hold -->|timeout| fail[Request fails]
  

Select the blocking strategy

The strategy is chosen in your reverse-proxy plugin configuration. Each proxy has its own syntax for opting a route into the blocking strategy. See Reverse proxies for the exact configuration of your plugin.

Blocking timeout

The plugin holds the request open only up to a timeout. If the instances are not ready in time, the request fails instead of hanging forever. Tune this with the blocking timeout. The server-side default is set with --strategy.blocking.default-timeout (see the CLI reference), and plugins can override it per route.

Related

• Strategies: how the blocking strategy works conceptually.
• Reverse proxies: the exact plugin syntax for each proxy.