From b5fa34e1a195b7dad0075370bb12c1be480a6c6b Mon Sep 17 00:00:00 2001
From: SChernykh <sergey.v.chernykh@gmail.com>
Date: Fri, 16 Jun 2023 15:51:33 +0200
Subject: [PATCH] Added support for multiple Monero hosts

Switch to the next host in list when P2Pool thinks current host is stuck or lagging
---
 .github/workflows/test-sync.yml |  18 ++--
 CMakeLists.txt                  |   2 +-
 docs/COMMAND_LINE.MD            |  13 +++
 src/console_commands.cpp        |  16 ++-
 src/p2p_server.cpp              |  34 +++++--
 src/p2p_server.h                |   2 +-
 src/p2pool.cpp                  | 170 +++++++++++++++++++-------------
 src/p2pool.h                    |  31 ++++--
 src/params.cpp                  |  83 +++++++++++++++-
 src/params.h                    |  30 +++++-
 src/pow_hash.cpp                |   3 +-
 src/side_chain.cpp              |  17 ++--
 src/side_chain.h                |   2 +-
 src/zmq_reader.cpp              | 103 +++++++++++++------
 src/zmq_reader.h                |  25 ++++-
 15 files changed, 402 insertions(+), 147 deletions(-)

diff --git a/.github/workflows/test-sync.yml b/.github/workflows/test-sync.yml
index 8d6e7e2..d5ff798 100644
--- a/.github/workflows/test-sync.yml
+++ b/.github/workflows/test-sync.yml
@@ -32,14 +32,13 @@ jobs:
         make -j$(nproc)
 
     - name: Run p2pool
-      timeout-minutes: 25
       run: |
         cd build
         mkdir data
         python ../tests/src/stratum_dummy.py 1 &
         python ../tests/src/stratum_dummy.py 2 &
         python ../tests/src/stratum_dummy.py 3 &
-        TSAN_OPTIONS="suppressions=../tests/src/tsan_sup.txt halt_on_error=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
+        TSAN_OPTIONS="suppressions=../tests/src/tsan_sup.txt halt_on_error=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
         grep 'Synchronization finished successfully' p2pool.log
 
     - name: Archive p2pool.log
@@ -110,14 +109,13 @@ jobs:
         make -j$(nproc)
 
     - name: Run p2pool
-      timeout-minutes: 20
       run: |
         cd build
         mkdir data
         python ../tests/src/stratum_dummy.py 1 &
         python ../tests/src/stratum_dummy.py 2 &
         python ../tests/src/stratum_dummy.py 3 &
-        MSAN_OPTIONS="halt_on_error=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
+        MSAN_OPTIONS="halt_on_error=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
         grep 'Synchronization finished successfully' p2pool.log
 
     - name: Archive p2pool.log
@@ -153,14 +151,13 @@ jobs:
         make -j$(nproc)
 
     - name: Run p2pool
-      timeout-minutes: 20
       run: |
         cd build
         mkdir data
         python ../tests/src/stratum_dummy.py 1 &
         python ../tests/src/stratum_dummy.py 2 &
         python ../tests/src/stratum_dummy.py 3 &
-        UBSAN_OPTIONS="suppressions=../tests/src/ubsan_sup.txt halt_on_error=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
+        UBSAN_OPTIONS="suppressions=../tests/src/ubsan_sup.txt halt_on_error=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
         grep 'Synchronization finished successfully' p2pool.log
 
     - name: Archive p2pool.log
@@ -196,14 +193,13 @@ jobs:
         make -j$(nproc)
 
     - name: Run p2pool
-      timeout-minutes: 20
       run: |
         cd build
         mkdir data
         python ../tests/src/stratum_dummy.py 1 &
         python ../tests/src/stratum_dummy.py 2 &
         python ../tests/src/stratum_dummy.py 3 &
-        ASAN_OPTIONS="detect_stack_use_after_return=1 atexit=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
+        ASAN_OPTIONS="detect_stack_use_after_return=1 atexit=1" ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
         grep 'Synchronization finished successfully' p2pool.log
 
     - name: Archive p2pool.log
@@ -236,14 +232,13 @@ jobs:
         make -j3
 
     - name: Run p2pool
-      timeout-minutes: 20
       run: |
         cd build
         mkdir data
         python ../tests/src/stratum_dummy.py 1 &
         python ../tests/src/stratum_dummy.py 2 &
         python ../tests/src/stratum_dummy.py 3 &
-        ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
+        ./p2pool --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
         grep 'Synchronization finished successfully' p2pool.log
 
     - name: Archive p2pool.log
@@ -276,14 +271,13 @@ jobs:
         & "C:\\Program Files\\Microsoft Visual Studio\\2022\\Enterprise\\Msbuild\\Current\\Bin\\amd64\\msbuild" /m /p:Configuration=Debug p2pool.vcxproj
 
     - name: Run p2pool
-      timeout-minutes: 20
       run: |
         cd build/Debug
         mkdir data
         Start-Process python -ArgumentList "../../tests/src/stratum_dummy.py 1"
         Start-Process python -ArgumentList "../../tests/src/stratum_dummy.py 2"
         Start-Process python -ArgumentList "../../tests/src/stratum_dummy.py 3"
-        ./p2pool.exe --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
+        ./p2pool.exe --host xmrnode.facspro.net --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --wallet 44MnN1f3Eto8DZYUWuE5XZNUtE3vcRzt2j6PzqWpPau34e6Cf4fAxt6X2MBmrm6F9YMEiMNjN6W4Shn4pLcfNAja621jwyg --data-api data --local-api --loglevel 6
         findstr /C:"Synchronization finished successfully" p2pool.log
 
     - name: Archive p2pool.log
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d4e99ac..2bf7222 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -120,7 +120,7 @@ if (WITH_RANDOMX)
 	set(SOURCES ${SOURCES} src/miner.cpp)
 endif()
 
-if (NOT STATIC_BINARY AND NOT STATIC_LIBS)
+if (NOT ((CMAKE_CXX_COMPILER_ID MATCHES MSVC) OR STATIC_BINARY OR STATIC_LIBS))
 	include(FindCURL)
 endif()
 
diff --git a/docs/COMMAND_LINE.MD b/docs/COMMAND_LINE.MD
index 307f31f..6ca2e09 100644
--- a/docs/COMMAND_LINE.MD
+++ b/docs/COMMAND_LINE.MD
@@ -34,4 +34,17 @@
 
 ### Example command line
 
+```
 p2pool.exe --host 127.0.0.1 --rpc-port 18081 --zmq-port 18083 --wallet YOUR_WALLET_ADDRESS --stratum 0.0.0.0:3333 --p2p 0.0.0.0:37889
+```
+
+### Multiple backup hosts
+
+You can have multiple hosts in command line. Each new host uses RPC and zmq-pub port numbers from the previous host (or default 18081/18083 if none were specified).
+
+In this example, you have local Monero node running on ports 18081/18083 (RPC/zmq-pub), and several backup nodes running on ports 18089/18084. If P2Pool detects that the node it's currently using is unavailable or stuck, it will cycle to the next node in the list.
+
+
+```
+p2pool.exe --host 127.0.0.1 --host xmr1.rs.me --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --host xmr3.rs.me --wallet YOUR_WALLET_ADDRESS
+```
diff --git a/src/console_commands.cpp b/src/console_commands.cpp
index 9a775a7..89a006b 100644
--- a/src/console_commands.cpp
+++ b/src/console_commands.cpp
@@ -140,7 +140,7 @@ typedef struct cmd {
 	cmdfunc *func;
 } cmd;
 
-static cmdfunc do_help, do_status, do_loglevel, do_addpeers, do_droppeers, do_showpeers, do_showworkers, do_showbans, do_outpeers, do_inpeers, do_exit, do_version;
+static cmdfunc do_help, do_status, do_loglevel, do_addpeers, do_droppeers, do_showpeers, do_showworkers, do_showbans, do_showhosts, do_nexthost, do_outpeers, do_inpeers, do_exit, do_version;
 
 #ifdef WITH_RANDOMX
 static cmdfunc do_start_mining, do_stop_mining;
@@ -155,6 +155,8 @@ static cmd cmds[] = {
 	{ STRCONST("peers"), "", "show all peers", do_showpeers },
 	{ STRCONST("workers"), "", "show all connected workers", do_showworkers },
 	{ STRCONST("bans"), "", "show all banned IPs", do_showbans },
+	{ STRCONST("hosts"), "", "show Monero hosts", do_showhosts },
+	{ STRCONST("next_host"), "", "switch to the next Monero host", do_nexthost },
 	{ STRCONST("outpeers"), "<N>", "set maximum number of outgoing connections", do_outpeers },
 	{ STRCONST("inpeers"), "<N>", "set maximum number of incoming connections", do_inpeers },
 #ifdef WITH_RANDOMX
@@ -240,6 +242,18 @@ static void do_showbans(p2pool* m_pool, const char* /* args */)
 	}
 }
 
+// cppcheck-suppress constParameterCallback
+static void do_showhosts(p2pool* m_pool, const char* /* args */)
+{
+	m_pool->print_hosts();
+}
+
+// cppcheck-suppress constParameterCallback
+static void do_nexthost(p2pool* m_pool, const char* /* args */)
+{
+	m_pool->reconnect_to_host();
+}
+
 // cppcheck-suppress constParameterCallback
 static void do_outpeers(p2pool* m_pool, const char* args)
 {
diff --git a/src/p2p_server.cpp b/src/p2p_server.cpp
index 216f17c..03ecddd 100644
--- a/src/p2p_server.cpp
+++ b/src/p2p_server.cpp
@@ -615,9 +615,9 @@ void P2PServer::load_peer_list()
 
 void P2PServer::load_monerod_peer_list()
 {
-	const Params& params = m_pool->params();
+	const Params::Host host = m_pool->current_host();
 
-	JSONRPCRequest::call(params.m_host, params.m_rpcPort, "/get_peer_list", params.m_rpcLogin, m_socks5Proxy,
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, "/get_peer_list", host.m_rpcLogin, m_socks5Proxy,
 		[this](const char* data, size_t size)
 		{
 #define ERR_STR "/get_peer_list RPC request returned invalid JSON "
@@ -1045,7 +1045,7 @@ void P2PServer::on_timer()
 	update_peer_list();
 	save_peer_list_async();
 	update_peer_connections();
-	check_zmq();
+	check_host();
 	check_block_template();
 	api_update_local_stats();
 }
@@ -1165,25 +1165,41 @@ void P2PServer::download_missing_blocks()
 	}
 }
 
-void P2PServer::check_zmq()
+void P2PServer::check_host()
 {
-	if ((m_timerCounter % 30) != 3) {
+	if (!m_pool->startup_finished()) {
 		return;
 	}
 
 	if (!m_pool->zmq_running()) {
 		LOGERR(1, "ZMQ is not running, restarting it");
-		m_pool->restart_zmq();
+		m_pool->reconnect_to_host();
 		return;
 	}
 
+	const uint64_t height = m_pool->miner_data().height;
+	const SideChain& side_chain = m_pool->side_chain();
+
+	// If the latest 5 side chain blocks are 2 or more Monero blocks ahead, then the node is probably stuck
+	uint32_t counter = 5;
+	for (const PoolBlock* b = side_chain.chainTip(); b && (b->m_txinGenHeight >= height + 2); b = side_chain.find_block(b->m_parent)) {
+		if (--counter == 0) {
+			const Params::Host host = m_pool->current_host();
+			LOGERR(1, host.m_displayName << " seems to be stuck, reconnecting");
+			m_pool->reconnect_to_host();
+			return;
+		}
+	}
+
 	const uint64_t cur_time = seconds_since_epoch();
 	const uint64_t last_active = m_pool->zmq_last_active();
 
+	// If there were no ZMQ messages in the last 5 minutes, then the node is probably stuck
 	if (cur_time >= last_active + 300) {
 		const uint64_t dt = static_cast<uint64_t>(cur_time - last_active);
-		LOGERR(1, "no ZMQ messages received from monerod in the last " << dt << " seconds, check your monerod/p2pool/network/firewall setup!!!");
-		m_pool->restart_zmq();
+		const Params::Host host = m_pool->current_host();
+		LOGERR(1, "no ZMQ messages received from " << host.m_displayName << " in the last " << dt << " seconds, check your monerod/p2pool/network/firewall setup!!!");
+		m_pool->reconnect_to_host();
 	}
 }
 
@@ -1230,6 +1246,8 @@ P2PServer::P2PClient::P2PClient()
 
 void P2PServer::on_shutdown()
 {
+	save_peer_list();
+
 	uv_timer_stop(&m_timer);
 	uv_close(reinterpret_cast<uv_handle_t*>(&m_timer), nullptr);
 	uv_close(reinterpret_cast<uv_handle_t*>(&m_broadcastAsync), nullptr);
diff --git a/src/p2p_server.h b/src/p2p_server.h
index c433fa6..3c4ec2b 100644
--- a/src/p2p_server.h
+++ b/src/p2p_server.h
@@ -191,7 +191,7 @@ private:
 
 	void flush_cache();
 	void download_missing_blocks();
-	void check_zmq();
+	void check_host();
 	void check_block_template();
 	void update_peer_connections();
 	void update_peer_list();
diff --git a/src/p2pool.cpp b/src/p2pool.cpp
index 8b7c384..a65cdcb 100644
--- a/src/p2pool.cpp
+++ b/src/p2pool.cpp
@@ -69,36 +69,14 @@ p2pool::p2pool(int argc, char* argv[])
 	}
 #endif
 
-	if (!p->m_wallet.valid()) {
-		LOGERR(1, "Invalid wallet address. Try \"p2pool --help\".");
-		throw std::exception();
-	}
-
-	m_hostStr = p->m_host;
-
-	if (p->m_socks5Proxy.empty()) {
-		if (p->m_dns) {
-			bool is_v6;
-			if (!resolve_host(p->m_host, is_v6)) {
-				LOGERR(1, "resolve_host failed for " << p->m_host);
-				throw std::exception();
-			}
-		}
-		else if (p->m_host.find_first_not_of("0123456789.:") != std::string::npos) {
-			LOGERR(1, "Can't resolve hostname " << p->m_host << " with DNS disabled");
+	for (Params::Host& h : p->m_hosts) {
+		if (!h.init_display_name(*p)) {
 			throw std::exception();
 		}
 	}
 
-	{
-		const bool changed = (p->m_host != m_hostStr);
-		const std::string rpc_port = ':' + std::to_string(p->m_rpcPort);
-		const std::string zmq_port = ":ZMQ:" + std::to_string(p->m_zmqPort);
-		m_hostStr += rpc_port + zmq_port;
-		if (changed) {
-			m_hostStr += " (" + p->m_host + ')';
-		}
-	}
+	m_currentHost = p->m_hosts.front();
+	m_currentHostIndex = 0;
 
 	hash pub, sec, eph_public_key;
 	generate_keys(pub, sec);
@@ -139,15 +117,17 @@ p2pool::p2pool(int argc, char* argv[])
 	}
 	m_stopAsync.data = this;
 
-	err = uv_async_init(uv_default_loop_checked(), &m_restartZMQAsync, on_restart_zmq);
+	err = uv_async_init(uv_default_loop_checked(), &m_reconnectToHostAsync, on_reconnect_to_host);
 	if (err) {
 		LOGERR(1, "uv_async_init failed, error " << uv_err_name(err));
 		throw std::exception();
 	}
-	m_restartZMQAsync.data = this;
+	m_reconnectToHostAsync.data = this;
 
+	uv_rwlock_init_checked(&m_currentHostLock);
 	uv_rwlock_init_checked(&m_mainchainLock);
 	uv_rwlock_init_checked(&m_minerDataLock);
+	uv_rwlock_init_checked(&m_ZMQReaderLock);
 	uv_mutex_init_checked(&m_foundBlocksLock);
 #ifdef WITH_RANDOMX
 	uv_mutex_init_checked(&m_minerLock);
@@ -204,8 +184,10 @@ p2pool::~p2pool()
 	}
 #endif
 
+	uv_rwlock_destroy(&m_currentHostLock);
 	uv_rwlock_destroy(&m_mainchainLock);
 	uv_rwlock_destroy(&m_minerDataLock);
+	uv_rwlock_destroy(&m_ZMQReaderLock);
 	uv_mutex_destroy(&m_foundBlocksLock);
 #ifdef WITH_RANDOMX
 	uv_mutex_destroy(&m_minerLock);
@@ -220,6 +202,20 @@ p2pool::~p2pool()
 	delete m_params;
 }
 
+void p2pool::print_hosts() const
+{
+	const Params::Host host = current_host();
+
+	for (const Params::Host& h : m_params->m_hosts) {
+		if (h.m_displayName == host.m_displayName) {
+			LOGINFO(0, log::LightCyan() << "-> " << h.m_displayName);
+		}
+		else {
+			LOGINFO(0, "   " << h.m_displayName);
+		}
+	}
+}
+
 bool p2pool::calculate_hash(const void* data, size_t size, uint64_t height, const hash& seed, hash& result, bool force_light_mode)
 {
 	return m_hasher->calculate(data, size, height, seed, result, force_light_mode);
@@ -297,17 +293,15 @@ void p2pool::handle_miner_data(MinerData& data)
 	{
 		WriteLock lock(m_mainchainLock);
 
-		m_mainchainByHeight[data.height].difficulty = data.difficulty;
+		ChainMain& c0 = m_mainchainByHeight[data.height];
+		c0.height = data.height;
+		c0.difficulty = data.difficulty;
 
-		ChainMain& c = m_mainchainByHeight[data.height - 1];
-		c.height = data.height - 1;
-		c.id = data.prev_id;
+		ChainMain& c1 = m_mainchainByHeight[data.height - 1];
+		c1.height = data.height - 1;
+		c1.id = data.prev_id;
 
-		// timestamp and reward is unknown here
-		c.timestamp = 0;
-		c.reward = 0;
-
-		m_mainchainByHash[c.id] = c;
+		m_mainchainByHash[c1.id] = c1;
 
 		cleanup_mainchain_data(data.height);
 	}
@@ -321,8 +315,11 @@ void p2pool::handle_miner_data(MinerData& data)
 	m_updateSeed = true;
 	update_median_timestamp();
 
+	const Params::Host host = current_host();
+
 	LOGINFO(2,
 		"new miner data\n---------------------------------------------------------------------------------------------------------------" <<
+		"\nhost                    = " << host.m_displayName <<
 		"\nmajor_version           = " << data.major_version <<
 		"\nheight                  = " << data.height <<
 		"\nprev_id                 = " << log::LightBlue() << data.prev_id << log::NoColor() <<
@@ -370,7 +367,7 @@ void p2pool::handle_miner_data(MinerData& data)
 			log::Stream s(buf);
 			s << "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_block_header_by_height\",\"params\":{\"height\":" << h << "}}\0";
 
-			JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, buf, m_params->m_rpcLogin, m_params->m_socks5Proxy,
+			JSONRPCRequest::call(host.m_address, host.m_rpcPort, buf, host.m_rpcLogin, m_params->m_socks5Proxy,
 				[this, h](const char* data, size_t size)
 				{
 					ChainMain block;
@@ -528,7 +525,7 @@ void p2pool::on_stop(uv_async_t* async)
 	uv_close(reinterpret_cast<uv_handle_t*>(&pool->m_submitBlockAsync), nullptr);
 	uv_close(reinterpret_cast<uv_handle_t*>(&pool->m_blockTemplateAsync), nullptr);
 	uv_close(reinterpret_cast<uv_handle_t*>(&pool->m_stopAsync), nullptr);
-	uv_close(reinterpret_cast<uv_handle_t*>(&pool->m_restartZMQAsync), nullptr);
+	uv_close(reinterpret_cast<uv_handle_t*>(&pool->m_reconnectToHostAsync), nullptr);
 
 	init_signals(pool, false);
 
@@ -603,7 +600,9 @@ void p2pool::submit_block() const
 	}
 	request.append("\"]}");
 
-	JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, request, m_params->m_rpcLogin, m_params->m_socks5Proxy,
+	const Params::Host host = current_host();
+
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, request, host.m_rpcLogin, m_params->m_socks5Proxy,
 		[height, diff, template_id, nonce, extra_nonce, sidechain_id, is_external](const char* data, size_t size)
 		{
 			rapidjson::Document doc;
@@ -714,13 +713,15 @@ void p2pool::download_block_headers(uint64_t current_height)
 	char buf[log::Stream::BUF_SIZE + 1] = {};
 	log::Stream s(buf);
 
+	const Params::Host host = current_host();
+
 	// First download 2 RandomX seeds
 	const uint64_t seed_heights[2] = { prev_seed_height, seed_height };
 	for (uint64_t height : seed_heights) {
 		s.m_pos = 0;
 		s << "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_block_header_by_height\",\"params\":{\"height\":" << height << "}}\0";
 
-		JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, buf, m_params->m_rpcLogin, m_params->m_socks5Proxy,
+		JSONRPCRequest::call(host.m_address, host.m_rpcPort, buf, host.m_rpcLogin, m_params->m_socks5Proxy,
 			[this, prev_seed_height, height](const char* data, size_t size)
 			{
 				ChainMain block;
@@ -749,8 +750,8 @@ void p2pool::download_block_headers(uint64_t current_height)
 	s.m_pos = 0;
 	s << "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_block_headers_range\",\"params\":{\"start_height\":" << start_height << ",\"end_height\":" << current_height - 1 << "}}\0";
 
-	JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, buf, m_params->m_rpcLogin, m_params->m_socks5Proxy,
-		[this, start_height, current_height](const char* data, size_t size)
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, buf, host.m_rpcLogin, m_params->m_socks5Proxy,
+		[this, start_height, current_height, host](const char* data, size_t size)
 		{
 			if (parse_block_headers_range(data, size) == current_height - start_height) {
 				update_median_timestamp();
@@ -762,15 +763,23 @@ void p2pool::download_block_headers(uint64_t current_height)
 						start_mining(m_params->m_minerThreads);
 					}
 #endif
-					try {
-						m_ZMQReader = new ZMQReader(m_params->m_host, m_params->m_zmqPort, m_params->m_socks5Proxy, this);
-					}
-					catch (const std::exception& e) {
-						LOGERR(1, "Couldn't start ZMQ reader: exception " << e.what());
-						PANIC_STOP();
+					{
+						WriteLock lock(m_ZMQReaderLock);
+
+						try {
+							m_ZMQReader = new ZMQReader(host.m_address, host.m_zmqPort, m_params->m_socks5Proxy, this);
+							m_zmqLastActive = seconds_since_epoch();
+						}
+						catch (const std::exception& e) {
+							LOGERR(1, "Couldn't start ZMQ reader: exception " << e.what());
+							PANIC_STOP();
+						}
 					}
+
 					api_update_network_stats();
 					get_miner_data();
+
+					m_startupFinished = true;
 				}
 			}
 			else {
@@ -857,17 +866,20 @@ void p2pool::stratum_on_block()
 
 void p2pool::get_info()
 {
-	JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_info\"}", m_params->m_rpcLogin, m_params->m_socks5Proxy,
+	const Params::Host host = current_host();
+
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_info\"}", host.m_rpcLogin, m_params->m_socks5Proxy,
 		[this](const char* data, size_t size)
 		{
 			parse_get_info_rpc(data, size);
 		},
-		[this](const char* data, size_t size)
+		[this, host](const char* data, size_t size)
 		{
 			if (size > 0) {
-				LOGWARN(1, "get_info RPC request failed: error " << log::const_buf(data, size) << ", trying again in 1 second");
+				LOGWARN(1, "get_info RPC request to " << host.m_displayName << " failed: error " << log::const_buf(data, size) << ", trying again in 1 second");
 				if (!m_stopped) {
 					std::this_thread::sleep_for(std::chrono::milliseconds(1000));
+					switch_host();
 					get_info();
 				}
 			}
@@ -970,17 +982,19 @@ void p2pool::parse_get_info_rpc(const char* data, size_t size)
 
 void p2pool::get_version()
 {
+	const Params::Host host = current_host();
+
 	const uint64_t t1 = microseconds_since_epoch();
 
-	JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_version\"}", m_params->m_rpcLogin, m_params->m_socks5Proxy,
-		[this, t1](const char* data, size_t size)
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_version\"}", host.m_rpcLogin, m_params->m_socks5Proxy,
+		[this, t1, host](const char* data, size_t size)
 		{
 			const double node_ping = static_cast<double>(microseconds_since_epoch() - t1) / 1e3;
 			if (node_ping < 100) {
-				LOGINFO(1, m_hostStr << " ping time is " << node_ping << " ms");
+				LOGINFO(1, host.m_displayName << " ping time is " << node_ping << " ms");
 			}
 			else {
-				LOGWARN(1, m_hostStr << " ping time is " << node_ping << " ms, this is too high for an efficient mining. Try to use a different node, or your own local node.");
+				LOGWARN(1, host.m_displayName << " ping time is " << node_ping << " ms, this is too high for an efficient mining. Try to use a different node, or your own local node.");
 			}
 			parse_get_version_rpc(data, size);
 		},
@@ -1047,23 +1061,25 @@ void p2pool::parse_get_version_rpc(const char* data, size_t size)
 	get_miner_data();
 }
 
-void p2pool::get_miner_data()
+void p2pool::get_miner_data(bool retry)
 {
 	if (m_getMinerDataPending) {
 		return;
 	}
 	m_getMinerDataPending = true;
 
-	JSONRPCRequest::call(m_params->m_host, m_params->m_rpcPort, "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_miner_data\"}", m_params->m_rpcLogin, m_params->m_socks5Proxy,
+	const Params::Host host = current_host();
+
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"get_miner_data\"}", host.m_rpcLogin, m_params->m_socks5Proxy,
 		[this](const char* data, size_t size)
 		{
 			parse_get_miner_data_rpc(data, size);
 		},
-		[this](const char* data, size_t size)
+		[this, host, retry](const char* data, size_t size)
 		{
 			if (size > 0) {
-				LOGWARN(1, "get_miner_data RPC request failed: error " << log::const_buf(data, size) << ", trying again in 1 second");
-				if (!m_stopped) {
+				LOGWARN(1, "get_miner_data RPC request to " << host.m_displayName << " failed: error " << log::const_buf(data, size) << (retry ? ", trying again in 1 second" : ""));
+				if (!m_stopped && retry) {
 					std::this_thread::sleep_for(std::chrono::milliseconds(1000));
 					m_getMinerDataPending = false;
 					get_miner_data();
@@ -1574,33 +1590,53 @@ void p2pool::stop()
 
 bool p2pool::zmq_running() const
 {
+	ReadLock lock(m_ZMQReaderLock);
 	return m_ZMQReader && m_ZMQReader->is_running();
 }
 
-void p2pool::restart_zmq()
+Params::Host p2pool::switch_host()
 {
-	// If p2pool is stopped, m_restartZMQAsync is most likely already closed
+	const Params::Host new_host = m_params->m_hosts[++m_currentHostIndex % m_params->m_hosts.size()];
+	{
+		WriteLock lock(m_currentHostLock);
+		m_currentHost = new_host;
+	}
+	return new_host;
+}
+
+void p2pool::reconnect_to_host()
+{
+	// If p2pool is stopped, m_reconnectToHostAsync is most likely already closed
 	if (m_stopped) {
 		return;
 	}
 
 	if (!is_main_thread()) {
-		uv_async_send(&m_restartZMQAsync);
+		uv_async_send(&m_reconnectToHostAsync);
 		return;
 	}
 
-	get_miner_data();
+	const Params::Host new_host = switch_host();
 
-	delete m_ZMQReader;
+	WriteLock lock(m_ZMQReaderLock);
+
+	ZMQReader* old_reader = m_ZMQReader;
 	m_ZMQReader = nullptr;
 
+	delete old_reader;
+
 	try {
-		m_ZMQReader = new ZMQReader(m_params->m_host, m_params->m_zmqPort, m_params->m_socks5Proxy, this);
+		ZMQReader* new_reader = new ZMQReader(new_host.m_address, new_host.m_zmqPort, m_params->m_socks5Proxy, this);
 		m_zmqLastActive = seconds_since_epoch();
+		m_ZMQReader = new_reader;
 	}
 	catch (const std::exception& e) {
 		LOGERR(1, "Couldn't restart ZMQ reader: exception " << e.what());
 	}
+
+	if (m_ZMQReader) {
+		get_miner_data(false);
+	}
 }
 
 int p2pool::run()
diff --git a/src/p2pool.h b/src/p2pool.h
index 0c6bc31..cac8848 100644
--- a/src/p2pool.h
+++ b/src/p2pool.h
@@ -18,11 +18,11 @@
 #pragma once
 
 #include "uv_util.h"
+#include "params.h"
 #include <map>
 
 namespace p2pool {
 
-struct Params;
 class RandomX_Hasher_Base;
 class BlockTemplate;
 class Mempool;
@@ -46,11 +46,18 @@ public:
 	bool stopped() const { return m_stopped; }
 	void stop();
 
-	const std::string& host_str() const { return m_hostStr; }
 	const Params& params() const { return *m_params; }
 	BlockTemplate& block_template() { return *m_blockTemplate; }
 	SideChain& side_chain() { return *m_sideChain; }
 
+	FORCEINLINE Params::Host current_host() const
+	{
+		ReadLock lock(m_currentHostLock);
+		return m_currentHost;
+	}
+
+	void print_hosts() const;
+
 	FORCEINLINE MinerData miner_data() const
 	{
 		ReadLock lock(m_minerDataLock);
@@ -98,24 +105,31 @@ public:
 	bool zmq_running() const;
 	uint64_t zmq_last_active() const { return m_zmqLastActive; }
 	uint64_t start_time() const { return m_startTime; }
-	void restart_zmq();
+	void reconnect_to_host();
+
+	bool startup_finished() const { return m_startupFinished.load(); }
 
 private:
 	p2pool(const p2pool&) = delete;
 	p2pool(p2pool&&) = delete;
 
+	Params::Host switch_host();
+
 	static void on_submit_block(uv_async_t* async) { reinterpret_cast<p2pool*>(async->data)->submit_block(); }
 	static void on_update_block_template(uv_async_t* async) { reinterpret_cast<p2pool*>(async->data)->update_block_template(); }
 	static void on_stop(uv_async_t*);
-	static void on_restart_zmq(uv_async_t* async) { reinterpret_cast<p2pool*>(async->data)->restart_zmq(); }
+	static void on_reconnect_to_host(uv_async_t* async) { reinterpret_cast<p2pool*>(async->data)->reconnect_to_host(); }
 
 	void submit_block() const;
 
 	std::atomic<bool> m_stopped;
 
-	std::string m_hostStr;
 	const Params* m_params;
 
+	mutable uv_rwlock_t m_currentHostLock;
+	Params::Host m_currentHost;
+	uint32_t m_currentHostIndex;
+
 	p2pool_api* m_api;
 	SideChain* m_sideChain;
 	RandomX_Hasher_Base* m_hasher;
@@ -143,7 +157,7 @@ private:
 	void get_version();
 	void parse_get_version_rpc(const char* data, size_t size);
 
-	void get_miner_data();
+	void get_miner_data(bool retry = true);
 	void parse_get_miner_data_rpc(const char* data, size_t size);
 
 	bool parse_block_header(const char* data, size_t size, ChainMain& c);
@@ -179,6 +193,8 @@ private:
 	StratumServer* m_stratumServer = nullptr;
 	P2PServer* m_p2pServer = nullptr;
 
+	std::atomic<bool> m_startupFinished{ false };
+
 #ifdef WITH_RANDOMX
 	uv_mutex_t m_minerLock;
 	Miner* m_miner = nullptr;
@@ -205,8 +221,9 @@ private:
 
 	std::atomic<uint64_t> m_zmqLastActive;
 	uint64_t m_startTime;
-	uv_async_t m_restartZMQAsync;
+	uv_async_t m_reconnectToHostAsync;
 
+	mutable uv_rwlock_t m_ZMQReaderLock;
 	ZMQReader* m_ZMQReader = nullptr;
 
 	hash m_getMinerDataHash;
diff --git a/src/params.cpp b/src/params.cpp
index b3eefb1..ea9a0ee 100644
--- a/src/params.cpp
+++ b/src/params.cpp
@@ -20,6 +20,8 @@
 #include "stratum_server.h"
 #include "p2p_server.h"
 
+constexpr char log_category_prefix[] = "P2Pool ";
+
 void p2pool_usage();
 
 namespace p2pool {
@@ -30,17 +32,35 @@ Params::Params(int argc, char* const argv[])
 		bool ok = false;
 
 		if ((strcmp(argv[i], "--host") == 0) && (i + 1 < argc)) {
-			m_host = argv[++i];
+			const char* address = argv[++i];
+
+			if (m_hosts.empty()) {
+				m_hosts.emplace_back(Host());
+				m_hosts.back().m_address = address;
+			}
+			else {
+				const Host& h = m_hosts.back();
+				m_hosts.emplace_back(address, h.m_rpcPort, h.m_zmqPort, "");
+			}
+
 			ok = true;
 		}
 
 		if ((strcmp(argv[i], "--rpc-port") == 0) && (i + 1 < argc)) {
-			m_rpcPort = std::min(std::max(strtoul(argv[++i], nullptr, 10), 1UL), 65535UL);
+			if (m_hosts.empty()) {
+				m_hosts.emplace_back(Host());
+			}
+
+			m_hosts.back().m_rpcPort = std::min(std::max(strtoul(argv[++i], nullptr, 10), 1UL), 65535UL);
 			ok = true;
 		}
 
 		if ((strcmp(argv[i], "--zmq-port") == 0) && (i + 1 < argc)) {
-			m_zmqPort = std::min(std::max(strtoul(argv[++i], nullptr, 10), 1UL), 65535UL);
+			if (m_hosts.empty()) {
+				m_hosts.emplace_back(Host());
+			}
+
+			m_hosts.back().m_zmqPort = std::min(std::max(strtoul(argv[++i], nullptr, 10), 1UL), 65535UL);
 			ok = true;
 		}
 
@@ -133,7 +153,11 @@ Params::Params(int argc, char* const argv[])
 		}
 
 		if ((strcmp(argv[i], "--rpc-login") == 0) && (i + 1 < argc)) {
-			m_rpcLogin = argv[++i];
+			if (m_hosts.empty()) {
+				m_hosts.emplace_back(Host());
+			}
+
+			m_hosts.back().m_rpcLogin = argv[++i];
 			ok = true;
 		}
 
@@ -172,6 +196,21 @@ Params::Params(int argc, char* const argv[])
 		}
 	}
 
+	auto invalid_host = [](const Host& h)
+	{
+		if (!h.valid()) {
+			LOGERR(1, "Invalid host " << h.m_address << ':' << h.m_rpcPort << ":ZMQ:" << h.m_zmqPort << ". Try \"p2pool --help\".");
+			return true;
+		}
+		return false;
+	};
+
+	m_hosts.erase(std::remove_if(m_hosts.begin(), m_hosts.end(), invalid_host), m_hosts.end());
+
+	if (m_hosts.empty()) {
+		m_hosts.emplace_back(Host());
+	}
+
 	if (m_stratumAddresses.empty()) {
 		const int stratum_port = DEFAULT_STRATUM_PORT;
 
@@ -185,7 +224,41 @@ Params::Params(int argc, char* const argv[])
 
 bool Params::valid() const
 {
-	return !m_host.empty() && m_rpcPort && m_zmqPort && m_wallet.valid();
+	if (!m_wallet.valid()) {
+		LOGERR(1, "Invalid wallet address. Try \"p2pool --help\".");
+		return false;
+	}
+
+	return true;
+}
+
+bool Params::Host::init_display_name(const Params& p)
+{
+	m_displayName = m_address;
+
+	if (p.m_socks5Proxy.empty()) {
+		if (p.m_dns) {
+			bool is_v6;
+			if (!resolve_host(m_address, is_v6)) {
+				LOGERR(1, "resolve_host failed for " << m_address);
+				return false;
+			}
+		}
+		else if (m_address.find_first_not_of("0123456789.:") != std::string::npos) {
+			LOGERR(1, "Can't resolve hostname " << m_address << " with DNS disabled");
+			return false;
+		}
+	}
+
+	const bool changed = (m_address != m_displayName);
+	const std::string rpc_port = ':' + std::to_string(m_rpcPort);
+	const std::string zmq_port = ":ZMQ:" + std::to_string(m_zmqPort);
+	m_displayName += rpc_port + zmq_port;
+	if (changed) {
+		m_displayName += " (" + m_address + ')';
+	}
+
+	return true;
 }
 
 } // namespace p2pool
diff --git a/src/params.h b/src/params.h
index f0fc96e..a23e7aa 100644
--- a/src/params.h
+++ b/src/params.h
@@ -27,9 +27,32 @@ struct Params
 
 	bool valid() const;
 
-	std::string m_host = "127.0.0.1";
-	uint32_t m_rpcPort = 18081;
-	uint32_t m_zmqPort = 18083;
+	struct Host
+	{
+		Host() : m_address("127.0.0.1"), m_rpcPort(18081), m_zmqPort(18083) {}
+
+		Host(const char* address, uint32_t rpcPort, uint32_t zmqPort, const char* rpcLogin)
+			: m_address(address)
+			, m_rpcPort(rpcPort)
+			, m_zmqPort(zmqPort)
+			, m_rpcLogin(rpcLogin)
+		{}
+
+		bool valid() const { return !m_address.empty() && m_rpcPort && m_zmqPort && (m_rpcPort != m_zmqPort); }
+
+		bool init_display_name(const Params& p);
+
+		std::string m_address;
+		uint32_t m_rpcPort;
+		uint32_t m_zmqPort;
+
+		std::string m_rpcLogin;
+
+		std::string m_displayName;
+	};
+
+	std::vector<Host> m_hosts;
+
 	bool m_lightMode = false;
 	Wallet m_wallet{ nullptr };
 	std::string m_stratumAddresses;
@@ -49,7 +72,6 @@ struct Params
 	uint32_t m_minerThreads = 0;
 	bool m_mini = false;
 	bool m_autoDiff = true;
-	std::string m_rpcLogin;
 	std::string m_socks5Proxy;
 	bool m_dns = true;
 	uint32_t m_p2pExternalPort = 0;
diff --git a/src/pow_hash.cpp b/src/pow_hash.cpp
index 4afe46f..2221c16 100644
--- a/src/pow_hash.cpp
+++ b/src/pow_hash.cpp
@@ -447,8 +447,9 @@ bool RandomX_Hasher_RPC::calculate(const void* data_ptr, size_t size, uint64_t h
 	volatile bool done = false;
 
 	const Params& params = m_pool->params();
+	const Params::Host host = m_pool->current_host();
 
-	JSONRPCRequest::call(params.m_host, params.m_rpcPort, buf, params.m_rpcLogin, params.m_socks5Proxy,
+	JSONRPCRequest::call(host.m_address, host.m_rpcPort, buf, host.m_rpcLogin, params.m_socks5Proxy,
 		[&result, &h](const char* data, size_t size)
 		{
 			rapidjson::Document doc;
diff --git a/src/side_chain.cpp b/src/side_chain.cpp
index e34c2d4..52f3ee3 100644
--- a/src/side_chain.cpp
+++ b/src/side_chain.cpp
@@ -67,7 +67,7 @@ SideChain::SideChain(p2pool* pool, NetworkType type, const char* pool_name)
 	, m_unclePenalty(20)
 	, m_precalcFinished(false)
 #ifdef DEV_TEST_SYNC
-	, m_synchronizedTime(0)
+	, m_firstPruneTime(0)
 #endif
 {
 	if (s_networkType == NetworkType::Invalid) {
@@ -1022,7 +1022,7 @@ void SideChain::print_status(bool obtain_sidechain_lock) const
 	}
 
 	LOGINFO(0, "status" <<
-		"\nMonero node               = " << m_pool->host_str() <<
+		"\nMonero node               = " << m_pool->current_host().m_displayName <<
 		"\nMain chain height         = " << m_pool->block_template().height() <<
 		"\nMain chain hashrate       = " << log::Hashrate(network_hashrate) <<
 		"\nSide chain ID             = " << (is_default() ? "default" : (is_mini() ? "mini" : m_consensusIdDisplayStr.c_str())) <<
@@ -1753,9 +1753,6 @@ void SideChain::update_chain_tip(const PoolBlock* block)
 					// Also clear cache because it has data from all old blocks now
 					clear_crypto_cache();
 					LOGINFO(0, log::LightCyan() << "SYNCHRONIZED");
-#ifdef DEV_TEST_SYNC
-					m_synchronizedTime = seconds_since_epoch();
-#endif
 				}
 			}
 			prune_old_blocks();
@@ -2064,7 +2061,14 @@ void SideChain::prune_old_blocks()
 		finish_precalc();
 
 #ifdef DEV_TEST_SYNC
-		if (m_pool && m_precalcFinished.load() && (cur_time >= m_synchronizedTime + 120)) {
+		if (m_firstPruneTime == 0) {
+			m_firstPruneTime = seconds_since_epoch();
+
+			// Test Monero node switching
+			m_pool->reconnect_to_host();
+		}
+
+		if (m_pool && m_precalcFinished.load() && (cur_time >= m_firstPruneTime + 120)) {
 			LOGINFO(0, log::LightGreen() << "[DEV] Synchronization finished successfully, stopping P2Pool now");
 			print_status(false);
 			P2PServer* server = m_pool->p2p_server();
@@ -2073,6 +2077,7 @@ void SideChain::prune_old_blocks()
 				server->print_bans();
 				server->show_peers_async();
 			}
+			m_pool->print_hosts();
 			m_pool->stop();
 		}
 #endif
diff --git a/src/side_chain.h b/src/side_chain.h
index 4ca1f91..5b2b51b 100644
--- a/src/side_chain.h
+++ b/src/side_chain.h
@@ -156,7 +156,7 @@ private:
 	std::atomic<bool> m_precalcFinished;
 
 #ifdef DEV_TEST_SYNC
-	uint64_t m_synchronizedTime;
+	uint64_t m_firstPruneTime;
 #endif
 
 	hash m_consensusHash;
diff --git a/src/zmq_reader.cpp b/src/zmq_reader.cpp
index 029db6d..121585d 100644
--- a/src/zmq_reader.cpp
+++ b/src/zmq_reader.cpp
@@ -25,7 +25,8 @@ static constexpr char log_category_prefix[] = "ZMQReader ";
 namespace p2pool {
 
 ZMQReader::ZMQReader(const std::string& address, uint32_t zmq_port, const std::string& proxy, MinerCallbackHandler* handler)
-	: m_address(address)
+	: m_monitor(nullptr)
+	, m_address(address)
 	, m_zmqPort(zmq_port)
 	, m_proxy(proxy)
 	, m_handler(handler)
@@ -61,29 +62,30 @@ ZMQReader::ZMQReader(const std::string& address, uint32_t zmq_port, const std::s
 
 	m_subscriber.set(zmq::sockopt::connect_timeout, 1000);
 
+	std::string addr = "tcp://127.0.0.1:" + std::to_string(m_publisherPort);
+	if (!connect(addr, false)) {
+		throw zmq::error_t(EFSM);
+	}
+
 	if (!m_proxy.empty()) {
 		m_subscriber.set(zmq::sockopt::socks_proxy, zmq::const_buffer(m_proxy.c_str(), m_proxy.length()));
 	}
 
-	std::string addr = "tcp://" + m_address + ':' + std::to_string(m_zmqPort);
-	if (!connect(addr)) {
+	addr = "tcp://" + m_address + ':' + std::to_string(m_zmqPort);
+	if (!connect(addr, true)) {
 		throw zmq::error_t(EFSM);
 	}
+	m_address = addr;
 
 	m_subscriber.set(zmq::sockopt::socks_proxy, zmq::const_buffer());
 
-	addr = "tcp://127.0.0.1:" + std::to_string(m_publisherPort);
-	if (!connect(addr)) {
-		throw zmq::error_t(EFSM);
-	}
-
 	m_subscriber.set(zmq::sockopt::subscribe, "json-full-chain_main");
 	m_subscriber.set(zmq::sockopt::subscribe, "json-full-miner_data");
 	m_subscriber.set(zmq::sockopt::subscribe, "json-minimal-txpool_add");
 
 	const int err = uv_thread_create(&m_worker, run_wrapper, this);
 	if (err) {
-		LOGERR(1, "failed to start ZMQ thread, error " << uv_err_name(err));
+		LOGERR(1, "failed to start ZMQ worker thread, error " << uv_err_name(err));
 		throw zmq::error_t(EMTHREAD);
 	}
 }
@@ -92,18 +94,43 @@ ZMQReader::~ZMQReader()
 {
 	LOGINFO(1, "stopping");
 
-	m_finished.exchange(true);
+	stop();
+	uv_thread_join(&m_worker);
+
+	delete m_monitor;
+
+	LOGINFO(1, "stopped");
+}
+
+void ZMQReader::stop()
+{
+	if (m_stopped.exchange(true)) {
+		return;
+	}
 
 	try {
-		const char msg[] = "json-minimal-txpool_add:[]";
-		m_publisher.send(zmq::const_buffer(msg, sizeof(msg) - 1));
-		uv_thread_join(&m_worker);
+		static constexpr char dummy_msg[] = "json-minimal-txpool_add:[]";
+		m_publisher.send(zmq::const_buffer(dummy_msg, sizeof(dummy_msg) - 1));
 	}
 	catch (const std::exception& e) {
 		LOGERR(1, "exception " << e.what());
 	}
 }
 
+void ZMQReader::monitor_thread(void* arg)
+{
+	LOGINFO(1, "monitor thread ready");
+
+	ZMQReader* r = reinterpret_cast<ZMQReader*>(arg);
+
+	do {} while (!r->m_stopped && r->m_monitor->m_connected && r->m_monitor->check_event(-1));
+
+	// If not connected anymore, shut down ZMQReader entirely
+	r->stop();
+
+	LOGINFO(1, "monitor thread stopped");
+}
+
 void ZMQReader::run_wrapper(void* arg)
 {
 	reinterpret_cast<ZMQReader*>(arg)->run();
@@ -112,8 +139,8 @@ void ZMQReader::run_wrapper(void* arg)
 
 void ZMQReader::run()
 {
-	m_threadRunning = true;
-	ON_SCOPE_LEAVE([this]() { m_threadRunning = false; });
+	m_workerThreadRunning = true;
+	ON_SCOPE_LEAVE([this]() { m_workerThreadRunning = false; });
 
 	zmq_msg_t message = {};
 
@@ -123,6 +150,13 @@ void ZMQReader::run()
 			throw zmq::error_t(errno);
 		}
 
+		const int err = uv_thread_create(&m_monitorThread, monitor_thread, this);
+		if (err) {
+			LOGERR(1, "failed to start ZMQ monitor thread, error " << uv_err_name(err));
+			throw zmq::error_t(EMTHREAD);
+		}
+		ON_SCOPE_LEAVE([this]() { uv_thread_join(&m_monitorThread); });
+
 		LOGINFO(1, "worker thread ready");
 
 		do {
@@ -131,7 +165,8 @@ void ZMQReader::run()
 				throw zmq::error_t(errno);
 			}
 
-			if (m_finished.load()) {
+			if (m_stopped) {
+				m_monitor->abort();
 				break;
 			}
 
@@ -145,19 +180,20 @@ void ZMQReader::run()
 	zmq_msg_close(&message);
 }
 
-bool ZMQReader::connect(const std::string& address)
+void ZMQReader::Monitor::on_event_connected(const zmq_event_t&, const char* address)
 {
-	struct ConnectMonitor : public zmq::monitor_t
-	{
-		void on_event_connected(const zmq_event_t&, const char* address) ZMQ_OVERRIDE
-		{
-			LOGINFO(1, "connected to " << address);
-			connected = true;
-		}
+	LOGINFO(1, "connected to " << address);
+	m_connected = true;
+}
 
-		bool connected = false;
-	} monitor;
+void ZMQReader::Monitor::on_event_disconnected(const zmq_event_t&, const char* address)
+{
+	LOGERR(1, "disconnected from " << address);
+	m_connected = false;
+}
 
+bool ZMQReader::connect(const std::string& address, bool keep_monitor)
+{
 	static uint64_t id = 0;
 
 	if (!id) {
@@ -165,7 +201,7 @@ bool ZMQReader::connect(const std::string& address)
 		id = (static_cast<uint64_t>(rd()) << 32) | static_cast<uint32_t>(rd());
 	}
 
-	char buf[log::Stream::BUF_SIZE + 1];
+	char buf[64];
 	log::Stream s(buf);
 	s << "inproc://p2pool-connect-mon-" << id << '\0';
 	++id;
@@ -173,16 +209,25 @@ bool ZMQReader::connect(const std::string& address)
 	using namespace std::chrono;
 	const auto start_time = steady_clock::now();
 
-	monitor.init(m_subscriber, buf);
+	Monitor* monitor = new Monitor();
+	monitor->init(m_subscriber, buf);
 	m_subscriber.connect(address);
 
-	while (!monitor.connected && monitor.check_event(-1)) {
+	while (!monitor->m_connected && monitor->check_event(-1)) {
 		if (duration_cast<milliseconds>(steady_clock::now() - start_time).count() >= 1000) {
 			LOGERR(1, "failed to connect to " << address);
+			delete monitor;
 			return false;
 		}
 	}
 
+	if (keep_monitor) {
+		m_monitor = monitor;
+	}
+	else {
+		delete monitor;
+	}
+
 	return true;
 }
 
diff --git a/src/zmq_reader.h b/src/zmq_reader.h
index d349d5f..b5ea64e 100644
--- a/src/zmq_reader.h
+++ b/src/zmq_reader.h
@@ -27,12 +27,29 @@ public:
 	ZMQReader(const std::string& address, uint32_t zmq_port, const std::string& proxy, MinerCallbackHandler* handler);
 	~ZMQReader();
 
-	bool is_running() const { return m_threadRunning.load(); }
+	bool is_running() const { return m_workerThreadRunning.load(); }
 
 private:
+	struct Monitor : public zmq::monitor_t {
+		Monitor() : m_connected(false) {}
+		Monitor(const Monitor&) = delete;
+
+		void on_event_connected(const zmq_event_t&, const char* address) ZMQ_OVERRIDE;
+		void on_event_disconnected(const zmq_event_t&, const char* address) ZMQ_OVERRIDE;
+
+		std::atomic<bool> m_connected;
+	} *m_monitor;
+
+	static void monitor_thread(void* arg);
+
+	uv_thread_t m_monitorThread{};
+
+private:
+	void stop();
+
 	static void run_wrapper(void* arg);
 	void run();
-	bool connect(const std::string& address);
+	bool connect(const std::string& address, bool keep_monitor);
 
 	void parse(char* data, size_t size);
 
@@ -46,8 +63,8 @@ private:
 	zmq::socket_t m_publisher{ m_context, ZMQ_PUB };
 	zmq::socket_t m_subscriber{ m_context, ZMQ_SUB };
 	uint16_t m_publisherPort = 0;
-	std::atomic<bool> m_finished{ false };
-	std::atomic<bool> m_threadRunning{ false };
+	std::atomic<bool> m_stopped{ false };
+	std::atomic<bool> m_workerThreadRunning{ false };
 
 	TxMempoolData m_tx;
 	MinerData m_minerData;