error_page 502 /502.html;
location = /502.html {
    root /usr/share/vmmgr/templates;
}

error_page 503 /503.html;
location = /503.html {
    root /usr/share/vmmgr/templates;
}

location = /vm-ping {
    add_header Content-Type text/plain;
    return 200 "vm-pong";
}