Merge pull request #6052 from jtru/better-systemd-integration-v2

Better systemd integration v2

src/Makefile

@@ -32,6 +32,7 @@ OPT=$(OPTIMIZATION)
 PREFIX?=/usr/local
 INSTALL_BIN=$(PREFIX)/bin
 INSTALL=install
+PKG_CONFIG?=pkg-config
 
 # Default allocator defaults to Jemalloc if it's not an ARM
 MALLOC=libc
@@ -140,6 +141,30 @@ endif
 # Include paths to dependencies
 FINAL_CFLAGS+= -I../deps/hiredis -I../deps/linenoise -I../deps/lua/src
 
+# Determine systemd support and/or build preference (defaulting to auto-detection)
+BUILD_WITH_SYSTEMD=no
+# If 'USE_SYSTEMD' in the environment is neither "no" nor "yes", try to
+# auto-detect libsystemd's presence and link accordingly.
+ifneq ($(USE_SYSTEMD),no)
+	LIBSYSTEMD_PKGCONFIG := $(shell $(PKG_CONFIG) --exists libsystemd && echo $$?)
+# If libsystemd cannot be detected, continue building without support for it
+# (unless a later check tells us otherwise)
+ifeq ($(LIBSYSTEMD_PKGCONFIG),0)
+	BUILD_WITH_SYSTEMD=yes
+endif
+endif
+ifeq ($(USE_SYSTEMD),yes)
+ifneq ($(LIBSYSTEMD_PKGCONFIG),0)
+$(error USE_SYSTEMD is set to "$(USE_SYSTEMD)", but $(PKG_CONFIG) cannot find libsystemd)
+endif
+# Force building with libsystemd
+	BUILD_WITH_SYSTEMD=yes
+endif
+ifeq ($(BUILD_WITH_SYSTEMD),yes)
+	FINAL_LIBS+=$(shell $(PKG_CONFIG) --libs libsystemd)
+	FINAL_CFLAGS+= -DHAVE_LIBSYSTEMD
+endif
+
 ifeq ($(MALLOC),tcmalloc)
 	FINAL_CFLAGS+= -DUSE_TCMALLOC
 	FINAL_LIBS+= -ltcmalloc

src/replication.c

@@ -1665,6 +1665,11 @@ void readSyncBulkPayload(connection *conn) {
     if (server.repl_backlog == NULL) createReplicationBacklog();
     serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Finished with success");
 
+    if (server.supervised_mode == SUPERVISED_SYSTEMD) {
+        redisCommunicateSystemd("STATUS=MASTER <-> REPLICA sync: Finished with success. Ready to accept connections.\n");
+        redisCommunicateSystemd("READY=1\n");
+    }
+
     /* Restart the AOF subsystem now that we finished the sync. This
      * will trigger an AOF rewrite, and when done will start appending
      * to the new file. */

src/server.c

@@ -3558,6 +3558,8 @@ int prepareForShutdown(int flags) {
     int nosave = flags & SHUTDOWN_NOSAVE;
 
     serverLog(LL_WARNING,"User requested shutdown...");
+    if (server.supervised_mode == SUPERVISED_SYSTEMD)
+        redisCommunicateSystemd("STOPPING=1\n");
 
     /* Kill all the Lua debugger forked sessions. */
     ldbKillForkedSessions();
@@ -3599,6 +3601,8 @@ int prepareForShutdown(int flags) {
     /* Create a new RDB file before exiting. */
     if ((server.saveparamslen > 0 && !nosave) || save) {
         serverLog(LL_NOTICE,"Saving the final RDB snapshot before exiting.");
+        if (server.supervised_mode == SUPERVISED_SYSTEMD)
+            redisCommunicateSystemd("STATUS=Saving the final RDB snapshot\n");
         /* Snapshotting. Perform a SYNC SAVE and exit */
         rdbSaveInfo rsi, *rsiptr;
         rsiptr = rdbPopulateSaveInfo(&rsi);
@@ -3609,6 +3613,8 @@ int prepareForShutdown(int flags) {
              * saving aborted, handling special stuff like slaves pending for
              * synchronization... */
             serverLog(LL_WARNING,"Error trying to save the DB, can't exit.");
+            if (server.supervised_mode == SUPERVISED_SYSTEMD)
+                redisCommunicateSystemd("STATUS=Error trying to save the DB, can't exit.\n");
             return C_ERR;
         }
     }
@@ -4774,61 +4780,19 @@ int redisSupervisedUpstart(void) {
     return 1;
 }
 
-int redisSupervisedSystemd(void) {
+int redisCommunicateSystemd(const char *sd_notify_msg) {
     const char *notify_socket = getenv("NOTIFY_SOCKET");
-    int fd = 1;
-    struct sockaddr_un su;
-    struct iovec iov;
-    struct msghdr hdr;
-    int sendto_flags = 0;
-
     if (!notify_socket) {
         serverLog(LL_WARNING,
                 "systemd supervision requested, but NOTIFY_SOCKET not found");
-        return 0;
     }
 
-    if ((strchr("@/", notify_socket[0])) == NULL || strlen(notify_socket) < 2) {
-        return 0;
-    }
-
-    serverLog(LL_NOTICE, "supervised by systemd, will signal readiness");
-    if ((fd = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) {
-        serverLog(LL_WARNING,
-                "Can't connect to systemd socket %s", notify_socket);
-        return 0;
-    }
-
-    memset(&su, 0, sizeof(su));
-    su.sun_family = AF_UNIX;
-    strncpy (su.sun_path, notify_socket, sizeof(su.sun_path) -1);
-    su.sun_path[sizeof(su.sun_path) - 1] = '\0';
-
-    if (notify_socket[0] == '@')
-        su.sun_path[0] = '\0';
-
-    memset(&iov, 0, sizeof(iov));
-    iov.iov_base = "READY=1";
-    iov.iov_len = strlen("READY=1");
-
-    memset(&hdr, 0, sizeof(hdr));
-    hdr.msg_name = &su;
-    hdr.msg_namelen = offsetof(struct sockaddr_un, sun_path) +
-        strlen(notify_socket);
-    hdr.msg_iov = &iov;
-    hdr.msg_iovlen = 1;
-
-    unsetenv("NOTIFY_SOCKET");
-#ifdef HAVE_MSG_NOSIGNAL
-    sendto_flags |= MSG_NOSIGNAL;
-#endif
-    if (sendmsg(fd, &hdr, sendto_flags) < 0) {
-        serverLog(LL_WARNING, "Can't send notification to systemd");
-        close(fd);
-        return 0;
-    }
-    close(fd);
-    return 1;
+    #ifdef HAVE_LIBSYSTEMD
+    (void) sd_notify(0, sd_notify_msg);
+    #else
+    UNUSED(sd_notify_msg);
+    #endif
+    return 0;
 }
 
 int redisIsSupervised(int mode) {
@@ -4839,12 +4803,17 @@ int redisIsSupervised(int mode) {
         if (upstart_job) {
             redisSupervisedUpstart();
         } else if (notify_socket) {
-            redisSupervisedSystemd();
+            server.supervised_mode = SUPERVISED_SYSTEMD;
+            serverLog(LL_WARNING,
+                "WARNING auto-supervised by systemd - you MUST set appropriate values for TimeoutStartSec and TimeoutStopSec in your service unit.");
+            return redisCommunicateSystemd("STATUS=Redis is loading...\n");
         }
     } else if (mode == SUPERVISED_UPSTART) {
         return redisSupervisedUpstart();
     } else if (mode == SUPERVISED_SYSTEMD) {
-        return redisSupervisedSystemd();
+        serverLog(LL_WARNING,
+            "WARNING supervised by systemd - you MUST set appropriate values for TimeoutStartSec and TimeoutStopSec in your service unit.");
+        return redisCommunicateSystemd("STATUS=Redis is loading...\n");
     }
 
     return 0;
@@ -5037,6 +5006,14 @@ int main(int argc, char **argv) {
             serverLog(LL_NOTICE,"Ready to accept connections");
         if (server.sofd > 0)
             serverLog(LL_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);
+        if (server.supervised_mode == SUPERVISED_SYSTEMD) {
+            if (!server.masterhost) {
+                redisCommunicateSystemd("STATUS=Ready to accept connections\n");
+                redisCommunicateSystemd("READY=1\n");
+            } else {
+                redisCommunicateSystemd("STATUS=Waiting for MASTER <-> REPLICA sync\n");
+            }
+        }
     } else {
         InitServerLast();
         sentinelIsRunning();

src/server.h

@@ -50,6 +50,10 @@
 #include <lua.h>
 #include <signal.h>
 
+#ifdef HAVE_LIBSYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
 typedef long long mstime_t; /* millisecond time type. */
 typedef long long ustime_t; /* microsecond time type. */
 
@@ -1544,6 +1548,7 @@ uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l);
 void exitFromChild(int retcode);
 size_t redisPopcount(void *s, long count);
 void redisSetProcTitle(char *title);
+int redisCommunicateSystemd(const char *sd_notify_msg);
 
 /* networking.c -- Networking and Client related operations */
 client *createClient(connection *conn);

utils/install_server.sh

@@ -73,6 +73,16 @@ if [ "$(id -u)" -ne 0 ] ; then
 	exit 1
 fi
 
+#bail if this system is managed by systemd
+_pid_1_exe="$(readlink -f /proc/1/exe)"
+if [ "${_pid_1_exe##*/}" = systemd ]
+then
+	echo "This systems seems to use systemd."
+	echo "Please take a look at the provided example service unit files in this directory, and adapt and install them. Sorry!"
+	exit 1
+fi
+unset _pid_1_exe
+
 if ! echo $REDIS_PORT | egrep -q '^[0-9]+$' ; then
 	_MANUAL_EXECUTION=true
 	#Read the redis port

utils/systemd-redis_multiple_servers@.service

@@ -0,0 +1,37 @@
+# example systemd template service unit file for multiple redis-servers
+#
+# You can use this file as a blueprint for your actual template service unit
+# file, if you intend to run multiple independent redis-server instances in
+# parallel using systemd's "template unit files" feature. If you do, you will
+# want to choose a better basename for your service unit by renaming this file
+# when copying it.
+#
+# Please take a look at the provided "systemd-redis_server.service" example
+# service unit file, too, if you choose to use this approach at managing
+# multiple redis-server instances via systemd.
+
+[Unit]
+Description=Redis data structure server - instance %i
+Documentation=https://redis.io/documentation
+# This template unit assumes your redis-server configuration file(s)
+# to live at /etc/redis/redis_server_<INSTANCE_NAME>.conf
+AssertPathExists=/etc/redis/redis_server_%i.conf
+#Before=your_application.service another_example_application.service
+#AssertPathExists=/var/lib/redis
+
+[Service]
+ExecStart=/usr/local/bin/redis-server /etc/redis/redis_server_%i.conf
+LimitNOFILE=10032
+NoNewPrivileges=yes
+#OOMScoreAdjust=-900
+#PrivateTmp=yes
+Type=notify
+TimeoutStartSec=infinity
+TimeoutStopSec=infinity
+UMask=0077
+#User=redis
+#Group=redis
+#WorkingDirectory=/var/lib/redis
+
+[Install]
+WantedBy=multi-user.target

utils/systemd-redis_server.service

@@ -0,0 +1,41 @@
+# example systemd service unit file for redis-server
+#
+# In order to use this as a template for providing a redis service in your
+# environment, _at the very least_ make sure to adapt the redis configuration
+# file you intend to use as needed (make sure to set "supervised systemd"), and
+# to set sane TimeoutStartSec and TimeoutStopSec property values in the unit's
+# "[Service]" section to fit your needs.
+#
+# Some properties, such as User= and Group=, are highly desirable for virtually
+# all deployments of redis, but cannot be provided in a manner that fits all
+# expectable environments. Some of these properties have been commented out in
+# this example service unit file, but you are highly encouraged to set them to
+# fit your needs.
+#
+# Please refer to systemd.unit(5), systemd.service(5), and systemd.exec(5) for
+# more information.
+
+[Unit]
+Description=Redis data structure server
+Documentation=https://redis.io/documentation
+#Before=your_application.service another_example_application.service
+#AssertPathExists=/var/lib/redis
+
+[Service]
+ExecStart=/usr/local/bin/redis-server --supervised systemd --daemonize no
+## Alternatively, have redis-server load a configuration file:
+#ExecStart=/usr/local/bin/redis-server /path/to/your/redis.conf
+LimitNOFILE=10032
+NoNewPrivileges=yes
+#OOMScoreAdjust=-900
+#PrivateTmp=yes
+Type=notify
+TimeoutStartSec=infinity
+TimeoutStopSec=infinity
+UMask=0077
+#User=redis
+#Group=redis
+#WorkingDirectory=/var/lib/redis
+
+[Install]
+WantedBy=multi-user.target