Explaining the architecture of distribution

Initially, we don't have an index and data when we start a single node. In this case, it means we have an empty cluster. When we create an index with the default settings, the cluster will take the following view:

As mentioned earlier, Elasticsearch creates five primary shards and a copy of each primary shard by default. But replicas do not appear in the preceding view. Why?

Let's look for the answer to our question by using the Cat API:

curl -XGET 'localhost:9200/_cat/shards'

my_index 4 p STARTED    0144b 192.168.1.22 Digitek
my_index 4 r UNASSIGNED
my_index 0 p STARTED    0144b 192.168.1.22 Digitek
my_index 0 r UNASSIGNED
my_index 3 p STARTED    0144b 192.168.1.22 Digitek
my_index 3 r UNASSIGNED
my_index 1 p STARTED    0144b 192.168.1.22 Digitek
my_index 1 r UNASSIGNED
my_index 2 p STARTED    0144b 192.168.1.22 Digitek
my_index 2 r UNASSIGNED

As you can see, there are five shards in our cluster, their states are STARTED, and there are other five...