Docker swarm

Question 1

How do you initialise the cluster on the swarm manager?

Answer 1

docker swarm init –advertise-addr

Question 2

How do you add workers to a swarm

Answer 2

docker swarm join –token :2377

Question 3

How do you list nodes in a swarm?

Answer 3

docker node ls

Question 4

How do you get the swarm token on the master node?

Answer 4

docker swarm join-token worker

docker swarm join-token manager

Question 5

How do you backup docker swarm?

Answer 5

systemctl stop docker
tar -zvcf backup.tar.gz /var/lib/docker/swarm
systemctl start docker

Question 6

How do restore from a docker swarm backup?

Answer 6

systemctl stop docker
rm -rf /var/lib/docker/swarm/*
tar -zxvf backup.tar.gz -C /var/lib/docker/swarm/

Question 7

What namespaces does docker use to isolate containers?

Answer 7

pid - process isolation
net - network isolation
ipc - interprocess communication
mnt - filesystem mount points
uts - kernel and version identifiers

Question 8

What does docker use to enforce resource limits?

Answer 8

cgroups - control groups