match

Defines the named test set used to verify server responses to health checks.

The following parameters can be configured:

send string;

sends a string to the server;

expect string | ~ regex;

a literal string (1.9.12) or a regular expression that the data obtained from the server should match. The regular expression is specified with the preceding “~*” modifier (for case-insensitive matching), or the “~” modifier (for case-sensitive matching).

Both send and expect parameters can contain hexadecimal literals with the prefix “\x” followed by two hex digits, for example, “\x80” (1.9.12).

Health check is passed if:

• the TCP connection was successfully established;
• the string from the send parameter, if specified, was sent;
• the data obtained from the server matched the string or regular expression from the expect parameter, if specified;
• the time elapsed does not exceed the value specified in the health_check_timeout directive.

Example:

upstream backend {
    zone     upstream_backend 10m;
    server   127.0.0.1:12345;
}

match http {
    send     "GET / HTTP/1.0\r\nHost: localhost\r\n\r\n";
    expect ~ "200 OK";
}

server {
    listen       12346;
    proxy_pass   backend;
    health_check match=http;
}

Only the first proxy_buffer_size bytes of data obtained from the server are examined.

This directive is available as part of our commercial subscription.