Docker Swarm: Failing to join in swarm cluster as manager node

Question

I created a swarm manager node on a VM instance of Ubuntu server 16.04 on google cloud with a static ip address. I want to join another VM instance of ubuntu having a static ip address. I'm unable to do so and getting error as time-out when try to join.

Answer 1

In most of these cases, it is primarily a firewall issue and hence it is recommended to check if firewall is not blocking the below ports on Google Cloud Platform. Please note that the below ports has to be opened for Swarm Mode to work -

TCP port 2377 for cluster management communications

TCP and UDP port 7946 for communication among nodes

UDP port 4789 for overlay network traffic

If you are planning on creating an overlay network with encryption (--opt encrypted), you will also need to ensure ip protocol 50 (ESP) traffic is allowed too.

Allowing Ports on Google Cloud Platform:

gcloud compute firewall-rules update [NAME] \
    [--allow=[[PROTOCOL][:PORT[-PORT]],…]] \
    [--description=[DESCRIPTION]] \
    [--destination-ranges=[CIDR_RANGE,…]] \
    [--priority=[PRIORITY]] \
    [--rules=[[PROTOCOL][:PORT[-PORT]],…]] \
    [--source-ranges=[[CIDR_RANGE],…]] \
    [--source-tags=[[TAG],…]] \
    [--target-tags=[[TAG],…]] \
    [--source-service-accounts=[EMAIL] \
    [--target-service-accounts=[EMAIL]

You need to enable the above ports either using GUI or GCLOUD.