Hi there.
I believe this topic was raised not once. But I couldn’t find any reasonable solution. So here it is…
I have deployed Zabbix in containers. I have only one host where 3 containers run: zabbix-server, zabbix-web-nginx-mysql, zabbix-agent. All 3 are defined in a single docker-compose.yaml:
version: '3.5'
networks:
zbx_net:
driver: bridge
services:
zabbix-server:
image: zabbix/zabbix-server-mysql:alpine-5.2-latest
ports:
- "10051:10051"
volumes:
- /etc/localtime:/etc/localtime:ro
- /etc/timezone:/etc/timezone:ro
- ./zbx_env/usr/lib/zabbix/alertscripts:/usr/lib/zabbix/alertscripts:ro
- ./zbx_env/usr/lib/zabbix/externalscripts:/usr/lib/zabbix/externalscripts:ro
- ./zbx_env/var/lib/zabbix/export:/var/lib/zabbix/export:rw
- ./zbx_env/var/lib/zabbix/modules:/var/lib/zabbix/modules:ro
- ./zbx_env/var/lib/zabbix/enc:/var/lib/zabbix/enc:ro
- ./zbx_env/var/lib/zabbix/ssh_keys:/var/lib/zabbix/ssh_keys:ro
- ./zbx_env/var/lib/zabbix/mibs:/var/lib/zabbix/mibs:ro
ulimits:
nproc: 65535
nofile:
soft: 20000
hard: 40000
env_file:
- .env_db_mysql
- .env_srv
secrets:
- MYSQL_USER
- MYSQL_PASSWORD
networks:
zbx_net:
aliases:
- zabbix-server
- zabbix-server-mysql
- zabbix-server-alpine-mysql
- zabbix-server-mysql-alpine
stop_grace_period: 30s
sysctls:
- net.ipv4.ip_local_port_range=1024 65000
- net.ipv4.conf.all.accept_redirects=0
- net.ipv4.conf.all.secure_redirects=0
- net.ipv4.conf.all.send_redirects=0
labels:
com.zabbix.description: "Zabbix server with MySQL database support"
com.zabbix.company: "Zabbix LLC"
com.zabbix.component: "zabbix-server"
com.zabbix.dbtype: "mysql"
com.zabbix.os: "alpine"
zabbix-web-nginx-mysql:
image: zabbix/zabbix-web-nginx-mysql:alpine-5.2-latest
ports:
- "8081:8080"
- "8443:8443"
volumes:
- /etc/localtime:/etc/localtime:ro
- /etc/timezone:/etc/timezone:ro
- ./zbx_env/etc/ssl/nginx:/etc/ssl/nginx:ro
- ./zbx_env/usr/share/zabbix/modules/:/usr/share/zabbix/modules/:ro
env_file:
- .env_db_mysql
- .env_web
secrets:
- MYSQL_USER
- MYSQL_PASSWORD
depends_on:
- zabbix-server
healthcheck:
test: ["CMD", "curl", "-f", "http://localhost:8080/"]
interval: 10s
timeout: 5s
retries: 3
start_period: 30s
networks:
zbx_net:
aliases:
- zabbix-web-nginx-mysql
- zabbix-web-nginx-alpine-mysql
- zabbix-web-nginx-mysql-alpine
stop_grace_period: 10s
sysctls:
- net.core.somaxconn=65535
labels:
com.zabbix.description: "Zabbix frontend on Nginx web-server with MySQL database support"
com.zabbix.company: "Zabbix LLC"
com.zabbix.component: "zabbix-frontend"
com.zabbix.webserver: "nginx"
com.zabbix.dbtype: "mysql"
com.zabbix.os: "alpine"
zabbix-agent:
image: zabbix/zabbix-agent:alpine-5.2-latest
ports:
- "10050:10050"
volumes:
- /etc/localtime:/etc/localtime:ro
- /etc/timezone:/etc/timezone:ro
- ./zbx_env/etc/zabbix/zabbix_agentd.d:/etc/zabbix/zabbix_agentd.d:ro
- ./zbx_env/var/lib/zabbix/modules:/var/lib/zabbix/modules:ro
- ./zbx_env/var/lib/zabbix/enc:/var/lib/zabbix/enc:ro
- ./zbx_env/var/lib/zabbix/ssh_keys:/var/lib/zabbix/ssh_keys:ro
env_file:
- .env_agent
privileged: true
pid: "host"
networks:
zbx_net:
aliases:
- zabbix-agent
- zabbix-agent-passive
- zabbix-agent-alpine
stop_grace_period: 5s
labels:
com.zabbix.description: "Zabbix agent"
com.zabbix.company: "Zabbix LLC"
com.zabbix.component: "zabbix-agentd"
com.zabbix.os: "alpine"
secrets:
MYSQL_USER:
file: ./.MYSQL_USER
MYSQL_PASSWORD:
file: ./.MYSQL_PASSWORD
All 3 containers are in same user-defined network. So according to Docker Compose documentation it should be enough that they are able to communicate. However if try to nc zabbix-server 10051 from zabbix-agent container the connection fails and I don’t see any connection attempt at zabbix-server.
I checked whether it can be caused by the firewall. I use nftables and created a rule allowing all traffic between 172.0.0.0/8 and 172.0.0.0/8. It helps partially in a way that I can connect to :10051 (like 172.26.0.1:10051). Although the zabbix-agent log still shows error that connection is refused so I think it still doesn’t work properly.
Anyway my primary concern is ability of containers to communicate to each other directly as it’s supposed to be. Also I tried to connect from zabbix-agent to zabbix-web-nginx-mysql:8081 and it also didn’t connect. So it’s my understanding that inter-container communication doesn’t work at all.
If I look at the zabbix_zbx_net network I can see all 3 containers are there:
[
{
"Name": "zabbix_zbx_net",
"Id": "def0d254c1077d3874c74ebd6f93a9a9895683a2cc97ffe53a0fa2524649f790",
"Created": "2020-12-22T10:02:59.55942359+01:00",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "172.27.0.0/16",
"Gateway": "172.27.0.1"
}
]
},
"Internal": false,
"Attachable": true,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"95ed96686a7607b5c8aa22bc86f69916dcc117ae118859a5254d3e001df70de9": {
"Name": "zabbix_zabbix-server_1",
"EndpointID": "98e7c97886308716b5bf85bf5c8a4bb9655df9e3d79d34a05c8b9d6bca10ae15",
"MacAddress": "02:42:ac:1b:00:03",
"IPv4Address": "172.27.0.3/16",
"IPv6Address": ""
},
"ab9216585795561226e608dc5f8a074de3d551f4e09f4caba48a111ec2d89c2b": {
"Name": "zabbix_zabbix-web-nginx-mysql_1",
"EndpointID": "0159042e1b64b7ac7f5ca3d675b7a855fa7d22aa42b4765877f4f09723f73307",
"MacAddress": "02:42:ac:1b:00:04",
"IPv4Address": "172.27.0.4/16",
"IPv6Address": ""
},
"d17b6314e3f0ade5af7f7bf770fa72f82677e3d6fe82b62bea3ae05567ceb836": {
"Name": "zabbix_zabbix-agent_1",
"EndpointID": "8799fe8af03e945fb020d39e66912a20501c08d7b715b3f4aeed531f57392c65",
"MacAddress": "02:42:ac:1b:00:02",
"IPv4Address": "172.27.0.2/16",
"IPv6Address": ""
}
},
"Options": {},
"Labels": {
"com.docker.compose.network": "zbx_net",
"com.docker.compose.project": "zabbix",
"com.docker.compose.version": "1.25.0"
}
}
]
So I don’t know what else can be checked.