Enabling swarm deployment on master branch:

-Extends the usage of POD_ADDRESS_RANGE
-Provides documentation

core/dovecot/conf/dovecot.conf

@@ -5,7 +5,7 @@ log_path = /dev/stderr
 protocols = imap pop3 lmtp sieve
 postmaster_address = {{ POSTMASTER }}@{{ DOMAIN }}
 hostname = {{ HOSTNAMES.split(",")[0] }}
-submission_host = {{ FRONT_ADDRESS }}
+submission_host = {{ FRONT_ADDRESS }} {{ POD_ADDRESS_RANGE }}
 
 service dict {
   unix_listener dict {

core/postfix/conf/main.cf

@@ -32,7 +32,7 @@ relayhost = {{ RELAYHOST }}
 recipient_delimiter = {{ RECIPIENT_DELIMITER }}
 
 # Only the front server is allowed to perform xclient
-smtpd_authorized_xclient_hosts={{ FRONT_ADDRESS }}
+smtpd_authorized_xclient_hosts={{ FRONT_ADDRESS }} {{ POD_ADDRESS_RANGE }}
 
 ###############
 # TLS

docs/swarm/master/README.md

@@ -0,0 +1,349 @@
+# Install Mailu on a docker swarm
+
+## Prequisites
+
+### Swarm
+
+In order to deploy Mailu on a swarm, you will first need to initialize the swarm:
+
+The main command will be:
+```bash
+docker swarm init --advertise-addr <IP_ADDR>
+```
+See https://docs.docker.com/engine/swarm/swarm-tutorial/create-swarm/
+
+If you want to add other managers or workers, please use:
+```bash
+docker swarm join --token xxxxx 
+```
+See https://docs.docker.com/engine/swarm/join-nodes/
+
+You have now a working swarm, and you can check its status with:
+```bash
+core@coreos-01 ~/git/Mailu/docs/swarm/1.5 $ docker node ls
+ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
+xhgeekkrlttpmtgmapt5hyxrb     black-pearl         Ready               Active                                  18.06.0-ce
+sczlqjgfhehsfdjhfhhph1nvb *   coreos-01           Ready               Active              Leader              18.03.1-ce
+mzrm9nbdggsfz4sgq6dhs5i6n     flying-dutchman     Ready               Active                                  18.06.0-ce
+```
+
+### Volume definition
+For data persistance (the Mailu services might be launched/relaunched on any of the swarm nodes), we need to have Mailu data stored in a manner accessible by every manager or worker in the swarm.
+Hereafter we will use a NFS share:
+```bash
+core@coreos-01 ~ $ showmount -e 192.168.0.30
+Export list for 192.168.0.30:
+/mnt/Pool1/pv            192.168.0.0
+```
+
+on the nfs server, I am using the following /etc/exports
+```bash
+$more /etc/exports
+/mnt/Pool1/pv -alldirs -mapall=root -network 192.168.0.0 -mask 255.255.255.0 
+```
+on the nfs server, I created the Mailu directory (in fact I copied a working Mailu set-up)
+```bash
+$mkdir /mnt/Pool1/pv/mailu
+```
+
+On your manager node, mount the nfs share to check that the share is available:
+```bash
+core@coreos-01 ~ $ sudo mount -t nfs 192.168.0.30:/mnt/Pool1/pv/mailu /mnt/local/
+```
+If this is ok, you can umount it:
+```bash
+core@coreos-01 ~ $ sudo umount /mnt/local/
+```
+
+
+### Networking mode
+On a swarm, the services are available (default mode) through a routing mesh managed by docker itself. With this mode, each service is given a virtual IP adress and docker manages the routing between this virtual IP and the container(s) providing this service. 
+
+In order to allow every (front & webmail) container to access the other services, we will use the variable POD_ADDRESS_RANGE.
+
+Let's create the mailu_default network:
+```bash
+core@coreos-01 ~ $ docker network create -d overlay --attachable mailu_default
+core@coreos-01 ~ $ docker network inspect mailu_default | grep Subnet
+                    "Subnet": "10.0.1.0/24",
+```
+In the docker-compose.yml file, we will then use POD_ADDRESS_RANGE = 10.0.1.0/24 
+
+Nota: on my setup, imap & smtp logs doesn't show the IPs from the front(s) container(s), but the IP of  "mailu_default-endpoint". So it might be sufficient to set POD_ADDRESS_RANGE to this specific ip (which can be found by inspecting mailu_default network)
+
+### Scalability
+- smtp and imap are scalable
+- front and webmail are scalable (pending POD_ADDRESS_RANGE is used), although the let's encrypt magic might not like it (race condidtion ? or risk to be banned by let's encrypt server if too many front containers attemps to renew the certs at the same time) 
+- redis, antispam, antivirus, fetchmail, admin, webdav have not been tested (hence replicas=1 in the following docker-compose.yml file)
+
+### Variable substitution and docker-compose.yml
+The docker stack deploy command doesn't support variable substitution in the .yml file itself (but we still can use .env file to pass variables to the services). As a consequence we need to adjust the docker-compose file in order to :
+- remove all variables : $VERSION , $BIND_ADDRESS4 , $BIND_ADDRESS6 , $ANTIVIRUS , $WEBMAIL , etc
+- change the way we define the volumes (nfs share in our case)
+- add a deploy section for every service
+
+### Docker compose 
+An example of docker-compose-stack.yml file is available here:
+
+```yaml
+
+version: '3.2'
+
+services:
+
+  front:
+    image: mailu/nginx:master
+    restart: always
+    env_file: .env
+    ports:
+      - target: 80
+        published: 80
+      - target: 443
+        published: 443
+      - target: 110
+        published: 110
+      - target: 143
+        published: 143
+      - target: 993
+        published: 993
+      - target: 995
+        published: 995
+      - target: 25
+        published: 25
+      - target: 465
+        published: 465
+      - target: 587
+        published: 587
+    volumes:
+#      - "$ROOT/certs:/certs"
+      - type: volume
+        source: mailu_certs
+        target: /certs
+    deploy:
+      replicas: 2
+
+  redis:
+    image: redis:alpine
+    restart: always
+    volumes:
+#      - "$ROOT/redis:/data"
+      - type: volume
+        source: mailu_redis
+        target: /data
+    deploy:
+      replicas: 1
+
+  imap:
+    image: mailu/dovecot:master
+    restart: always
+    env_file: .env
+    environment:
+      - POD_ADDRESS_RANGE=10.0.1.0/24
+    volumes:
+#      - "$ROOT/data:/data"
+      - type: volume
+        source: mailu_data
+        target: /data
+#      - "$ROOT/mail:/mail"
+      - type: volume
+        source: mailu_mail
+        target: /mail
+#      - "$ROOT/overrides:/overrides"
+      - type: volume
+        source: mailu_overrides
+        target: /overrides
+    depends_on:
+      - front
+    deploy:
+      replicas: 2
+
+  smtp:
+    image: mailu/postfix:master
+    restart: always
+    env_file: .env
+    environment:
+      - POD_ADDRESS_RANGE=10.0.1.0/24
+    volumes:
+#      - "$ROOT/data:/data"
+      - type: volume
+        source: mailu_data
+        target: /data
+#      - "$ROOT/overrides:/overrides"
+      - type: volume
+        source: mailu_overrides
+        target: /overrides
+    depends_on:
+      - front
+    deploy:
+      replicas: 2
+
+  antispam:
+    image: mailu/rspamd:master
+    restart: always
+    env_file: .env
+    environment:
+      - POD_ADDRESS_RANGE=10.0.1.0/24
+    depends_on:
+      - front
+    volumes:
+#      - "$ROOT/filter:/var/lib/rspamd"
+      - type: volume
+        source: mailu_filter
+        target: /var/lib/rspamd
+#      - "$ROOT/dkim:/dkim"
+      - type: volume
+        source: mailu_dkim
+        target: /dkim
+#      - "$ROOT/overrides/rspamd:/etc/rspamd/override.d"
+      - type: volume
+        source: mailu_overrides_rspamd
+        target: /etc/rspamd/override.d
+    deploy:
+      replicas: 1
+
+  antivirus:
+    image: mailu/none:master
+    restart: always
+    env_file: .env
+    volumes:
+#      - "$ROOT/filter:/data"
+      - type: volume
+        source: mailu_filter
+        target: /data
+    deploy:
+      replicas: 1
+
+  webdav:
+    image: mailu/none:master
+    restart: always
+    env_file: .env
+    volumes:
+#      - "$ROOT/dav:/data"
+      - type: volume
+        source: mailu_dav
+        target: /data
+    deploy:
+      replicas: 1
+
+  admin:
+    image: mailu/admin:master
+    restart: always
+    env_file: .env
+    volumes:
+#      - "$ROOT/data:/data"
+      - type: volume
+        source: mailu_data
+        target: /data
+#      - "$ROOT/dkim:/dkim"
+      - type: volume
+        source: mailu_dkim
+        target: /dkim
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    depends_on:
+      - redis
+    deploy:
+      replicas: 1
+
+  webmail:
+    image: "mailu/roundcube:master"
+    restart: always
+    env_file: .env
+    volumes:
+#      - "$ROOT/webmail:/data"
+      - type: volume
+        source: mailu_data
+        target: /data
+    depends_on:
+      - imap
+    deploy:
+      replicas: 2
+
+  fetchmail:
+    image: mailu/fetchmail:master
+    restart: always
+    env_file: .env
+    volumes:
+#      - "$ROOT/data:/data"
+      - type: volume
+        source: mailu_data
+        target: /data
+    deploy:
+      replicas: 1
+
+networks:
+  default:
+    external:
+      name: mailu_default
+
+volumes:
+  mailu_filter:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/filter"
+  mailu_dkim:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/dkim"
+  mailu_overrides_rspamd:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/overrides/rspamd"
+  mailu_data:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/data"
+  mailu_mail:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/mail"
+  mailu_overrides:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/overrides"
+  mailu_dav:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/dav"
+  mailu_certs:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/certs"
+  mailu_redis:
+    driver_opts:
+      type: "nfs"
+      o: "addr=192.168.0.30,nolock,soft,rw"
+      device: ":/mnt/Pool1/pv/mailu/redis"
+```
+
+### Deploy Mailu on the docker swarm
+Run the following command:
+```bash
+docker stack deploy -c docker-compose-stack.yml mailu
+```
+See how the services are being deployed:
+```bash
+core@coreos-01 ~ $ docker service ls
+ID                  NAME                                 MODE                REPLICAS            IMAGE                                     PORTS
+ywnsetmtkb1l        mailu_antivirus                      replicated          1/1                 mailu/none:1.5
+pqokiaz0q128        mailu_fetchmail                      replicated          1/1                 mailu/fetchmail:1.5
+```
+check a specific service:
+```bash
+core@coreos-01 ~ $ docker service ps mailu_fetchmail
+ID                  NAME                IMAGE                 NODE                DESIRED STATE       CURRENT STATE         ERROR               PORTS
+tbu8ppgsdffj        mailu_fetchmail.1   mailu/fetchmail:1.5   coreos-01           Running             Running 11 days ago
+```
+
+### Remove the stack
+Run the follwoing command:
+```bash
+core@coreos-01 ~ $ docker stack rm mailu
+```

services/rspamd/conf/worker-controller.inc

@@ -1,3 +1,3 @@
 bind_socket = "*:11334";
 password = "mailu";
-secure_ip = "{{ FRONT_ADDRESS }}";
+secure_ip = "{{ FRONT_ADDRESS }} {{ POD_ADDRESS_RANGE }}";