public boolean serverExists(final Endpoint addr) {
        if (addr.getIp().equals(Utils.IP_ANY)) {
            return this.addrSet.contains(new Endpoint(Utils.IP_ANY, addr.getPort()));
        }
        return this.addrSet.contains(addr);
    }
Return true when RPC service is registered.
jraft-core/src/main/java/com/alipay/sofa/jraft/NodeManager.java