When initializing the Docker swarm cluster, depending on the IPAM driver, a subnet network is defined. On second node (worker) check that overlay-to-attach network does not exist: ~]# docker network lsĮdd78417b9df docker_gwbridge bridge localĬreate a second centos2 container on another node and join it to overlay-to-attach network: ~]# docker run -dit –name centos2 –network overlay-to-attach centos ping ĭ6e6c89f62e661f0daf89df40e8b7b383cd8ff8419c2980259f229acc31d5e5eįrom first container ping second one: ~]# docker exec centos ping centos2 If you want to create an overlay network to communicate services and standalone containers with standalone containers on other docker daemons, use the attach parameter: ~]# docker network create -d overlay –attachable overlay-to-attachĬreate container centos and attach it to overlay-to-attach network: ~]# docker run -d –name centos –network overlay-to-attach centos ping Ġce108196f14c225339acb7f4528179ad21b4229390586a39651a5a2a46c6955 If you want to create own overlay network it done this way: ~]# docker network create -d overlay customoverlayĮxample 3 (Creating an Overlay Network for Communication between Services and standalone Containers) When swarm cluster is initialized, a default ingress overlay network is created: ~]# docker network ls More on this in the Docker swarm article. It is assumed that a 3-node swarm cluster has already been created. In this example, we will create an overlay network. Packet arrives at host1 physical interface, is encapsulated and the original packet is forwarded to the container by the destination IP address.Encapsulated packet is send through VXLAN tunnel and routed by physical devices.
#DOCKER NETWORK RM MAC#
Ethernet frame is encapsulated with VXLAN header containing source and destination IP and MAC address of hosts.To resolve MAC address, Container 2 sends ARP request which is answered by the operating system.Container2 generates an Ethernet frame with MAC and IP address of container1.Because container reside on same network embedded DNS servers responds to container2 with info Container 2 sends DNS requests for container1.The Docker engine does not create an overlay network on hosts that do run services. To summarize, the overlay network is only used between containers, while the additional network serves to connect the container to the outside world, and communication between the containers is not allowed on this network. Docker Engine automatically creates a VXLAN support without the need for additional setup.Įngine also creates an additional network to access the outside world. Docker Swarm initialization creates an overlay ingress network.
#DOCKER NETWORK RM DRIVER#
Overlay Driver Network Architectureĭocker overlay network driver is an integral part of the Docker installation that handles high-quality multi-host communication. In the introduction, we’re talking about architecture, external traffic going to Docker services, how DNS services works, different types of load balancing, and finally security and encryption. The Docker overlay network uses VXLAN technology to connect containers in the L2 network located on different hosts. In this section, we will explain the network used when operating the Docker swarm cluster.
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