Let's check the distribution of information between the nodes using a distributed key-value storage, that is, if we added records to one node, then they should spread to other nodes, and it should not have a hard-coded Master node. Since Consul consists of one executable file, download it from the official website at the linkhtml on each node:

wget-O consul.zip

unzip consul.zip

rm -f consul.zip

Now you need to start one node, for now, as master consul -server -ui , and others as slave consul -server -ui and consul -server -ui . After that, we will stop Consul, which is in master mode, and launch it as an equal, as a result of Consul – they will re-elect the temporary leader, and in case of a yoke of failure, they will re-elect again. Let's check the work of our cluster consul members :

consul members;

And so let's check the distribution of information in our storage:

curl -X PUT -d 'value1' .....: 8500 / v1 / kv / group1 / key1

curl -s .....: 8500 / v1 / kv / group1 / key1

curl -s .....: 8500 / v1 / kv / group1 / key1

curl -s .....: 8500 / v1 / kv / group1 / key1

Let's set up service monitoring, for more details see the documentationhtml #telemetry, for that .... https://medium.com/southbridge/monitoring-consul-with-statsd-exporter-and-prometheus-bad8bee3961b

In order not to configure, we will use the container and mode for development with the already configured IP address at 172.17.0.2:

essh @ kubernetes-master: ~ $ mkdir consul && cd $ _

essh @ kubernetes-master: ~ / consul $ docker run -d –name = dev-consul -e CONSUL_BIND_INTERFACE = eth0 consul

Unable to find image 'consul: latest' locally

latest: Pulling from library / consul

e7c96db7181b: Pull complete

3404d2df15cb: Pull complete

1b2797650ac6: Pull complete

42eaf145982e: Pull complete

cef844389e8c: Pull complete

bc7449359c58: Pull complete

Digest: sha256: 94cdbd83f24ec406da2b5d300a112c14cf1091bed8d6abd49609e6fe3c23f181

Status: Downloaded newer image for consul: latest

c6079f82500a41f878d2c513cf37d45ecadd3fc40998cd35020c604eb5f934a1

essh @ kubernetes-master: ~ / consul $ docker inspect dev-consul | jq '. [] | .NetworkSettings.Networks.bridge.IPAddress'

"172.17.0.4"

essh @ kubernetes-master: ~ / consul $ docker run -d –name = consul_follower_1 -e CONSUL_BIND_INTERFACE = eth0 consul agent -dev -join = 172.17.0.4

8ec88680bc632bef93eb9607612ed7f7f539de9f305c22a7d5a23b9ddf8c4b3e

essh @ kubernetes-master: ~ / consul $ docker run -d –name = consul_follower_2 -e CONSUL_BIND_INTERFACE = eth0 consul agent -dev -join = 172.17.0.4

babd31d7c5640845003a221d725ce0a1ff83f9827f839781372b1fcc629009cb

essh @ kubernetes-master: ~ / consul $ docker exec -t dev-consul consul members

Node Address Status Type Build Protocol DC Segment

53cd8748f031 172.17.0.5:8301 left server 1.6.1 2 dc1 <all>

8ec88680bc63 172.17.0.5:8301 alive server 1.6.1 2 dc1 <all>

babd31d7c564 172.17.0.6:8301 alive server 1.6.1 2 dc1 <all>

essh @ kubernetes-master: ~ / consul $ curl -X PUT -d 'value1' 172.17.0.4:8500/v1/kv/group1/key1

true

essh @ kubernetes-master: ~ / consul $ curl $ (docker inspect dev-consul | jq -r '. [] | .NetworkSettings.Networks.bridge.IPAddress'): 8500 / v1 / kv / group1 / key1

[

{

"LockIndex": 0,

"Key": "group1 / key1",

"Flags": 0,

"Value": "dmFsdWUx",

"CreateIndex": 277,

"ModifyIndex": 277

}

]

essh @ kubernetes-master: ~ / consul $ firefox $ (docker inspect dev-consul | jq -r '. [] | .NetworkSettings.Networks.bridge.IPAddress'): 8500 / ui

With the determination of the location of the containers, it is necessary to provide authorization; for this, key stores are used.

dockerd -H fd: // –cluster-store = consul: //192.168.1.6: 8500 –cluster-advertise = eth0: 2376

* –cluster-store – you can get data about keys

* –cluster-advertise – can be saved

docker network create –driver overlay –subnet 192.168.10.0/24 demo-network

docker network ls

Simple clustering

In this article, we will not consider how to create a cluster manually, but will use two tools: Docker Swarm and Google Kubernetes – the most popular and most common solutions. Docker Swarm is simpler, it is part of Docker and therefore has the largest audience (subjectively), and Kubernetes provides much more capabilities, more tool integrations (for example, distributed storage for Volume), support in popular clouds, and more easily scalable for large projects (large abstraction, component approach).