3.0 config replication

Author: andreyaksenov

doc/code_snippets/snippets/sharding/README.md

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+# Sharded cluster
+
+A sample application demonstrating how to configure a [sharded](https://www.tarantool.io/en/doc/latest/concepts/sharding/) cluster.
+
+## Running
+
+To run the cluster, go to the `sharding` directory in the terminal and perform the following steps:
+
+1. Install `vshard`:
+
+   ```console
+   $ tt rocks install vshard
+   ```
+   
+2. Run the cluster:
+
+   ```console
+   $ tt start sharded_cluster
+   ```
+
+3. Connect to the router:
+
+   ```console
+   $ tt connect sharded_cluster:router-a-001
+   ```
+
+4. Insert test data:
+
+   ```console
+   sharded_cluster:router-a-001> insert_data()
+   ---
+   ...
+   ```
+   
+5. Connect to storages in different replica sets to see how data is distributed across nodes:
+
+   a. `storage-a-001`:
+
+      ```console
+      sharded_cluster:storage-a-001> box.space.bands:select()
+      ---
+      - - [1, 614, 'Roxette', 1986]
+        - [2, 986, 'Scorpions', 1965]
+        - [5, 755, 'Pink Floyd', 1965]
+        - [7, 998, 'The Doors', 1965]
+        - [8, 762, 'Nirvana', 1987]
+      ...
+      ```
+   
+   b. `storage-b-001`:
+
+      ```console
+      sharded_cluster:storage-b-001> box.space.bands:select()
+      ---
+      - - [3, 11, 'Ace of Base', 1987]
+        - [4, 42, 'The Beatles', 1960]
+        - [6, 55, 'The Rolling Stones', 1962]
+        - [9, 299, 'Led Zeppelin', 1968]
+        - [10, 167, 'Queen', 1970]
+      ...
+      ```

doc/code_snippets/snippets/sharding/instances.enabled/sharded_cluster/config.yaml

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+credentials:
+  users:
+    replicator:
+      password: 'topsecret'
+      roles: [replication]
+    storage:
+      password: 'secret'
+      roles: [super]
+
+iproto:
+  advertise:
+    peer: replicator@
+    sharding: storage@
+
+sharding:
+  bucket_count: 1000
+
+groups:
+  storages:
+    app:
+      module: storage
+    sharding:
+      roles: [storage]
+    replication:
+      failover: manual
+    replicasets:
+      storage-a:
+        leader: storage-a-001
+        instances:
+          storage-a-001:
+            iproto:
+              listen: 127.0.0.1:3301
+          storage-a-002:
+            iproto:
+              listen: 127.0.0.1:3302
+      storage-b:
+        leader: storage-b-002
+        instances:
+          storage-b-001:
+            iproto:
+              listen: 127.0.0.1:3303
+          storage-b-002:
+            iproto:
+              listen: 127.0.0.1:3304
+  routers:
+    app:
+      module: router
+    sharding:
+      roles: [router]
+    replicasets:
+      router-a:
+        instances:
+          router-a-001:
+            iproto:
+              listen: 127.0.0.1:3300

doc/code_snippets/snippets/sharding/instances.enabled/sharded_cluster/instances.yaml

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+sharded_cluster.storage-a-001:
+sharded_cluster.storage-a-002:
+sharded_cluster.storage-b-001:
+sharded_cluster.storage-b-002:
+sharded_cluster.router-a-001:

doc/code_snippets/snippets/sharding/instances.enabled/sharded_cluster/router.lua

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+local vshard = require('vshard')
+
+vshard.router.bootstrap()
+
+function put(id, band_name, year)
+    local bucket_id = vshard.router.bucket_id_mpcrc32({ id })
+    vshard.router.callrw(bucket_id, 'put', { id, bucket_id, band_name, year })
+end
+
+function get(id)
+    local bucket_id = vshard.router.bucket_id_mpcrc32({ id })
+    return vshard.router.callro(bucket_id, 'get', { id })
+end
+
+function insert_data()
+    put(1, 'Roxette', 1986)
+    put(2, 'Scorpions', 1965)
+    put(3, 'Ace of Base', 1987)
+    put(4, 'The Beatles', 1960)
+    put(5, 'Pink Floyd', 1965)
+    put(6, 'The Rolling Stones', 1962)
+    put(7, 'The Doors', 1965)
+    put(8, 'Nirvana', 1987)
+    put(9, 'Led Zeppelin', 1968)
+    put(10, 'Queen', 1970)
+end

doc/code_snippets/snippets/sharding/instances.enabled/sharded_cluster/storage.lua

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+box.schema.create_space('bands', {
+    format = {
+        { name = 'id', type = 'unsigned' },
+        { name = 'bucket_id', type = 'unsigned' },
+        { name = 'band_name', type = 'string' },
+        { name = 'year', type = 'unsigned' }
+    },
+    if_not_exists = true
+})
+box.space.bands:create_index('id', { parts = { 'id' }, if_not_exists = true })
+box.space.bands:create_index('bucket_id', { parts = { 'id' }, unique = false, if_not_exists = true })
+
+function put(id, bucket_id, band_name, year)
+    box.space.bands:insert({ id, bucket_id, band_name, year })
+end
+
+function get(id)
+    local tuple = box.space.bands:get(id)
+    if tuple == nil then
+        return nil
+    end
+    return { tuple.id, tuple.band_name, tuple.year }
+end

doc/code_snippets/snippets/sharding/tt.yaml

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+tt:
+  modules:
+    # Directory where the external modules are stored.
+    directory: "modules"
+
+  app:
+    # Directory that stores various instance runtime
+    # artifacts like console socket, PID file, etc.
+    run_dir: "var/run"
+
+    # Directory that stores log files.
+    log_dir: var/log
+
+    # The maximum size in MB of the log file before it gets rotated.
+    log_maxsize: 100
+
+    # The maximum number of days to retain old log files.
+    log_maxage: 8
+
+    # The maximum number of old log files to retain.
+    log_maxbackups: 10
+
+    # Restart instance on failure.
+    restart_on_failure: false
+
+    # Directory where write-ahead log (.xlog) files are stored.
+    wal_dir: "var/lib"
+
+    # Directory where memtx stores snapshot (.snap) files.
+    memtx_dir: "var/lib"
+
+    # Directory where vinyl files or subdirectories will be stored.
+    vinyl_dir: "var/lib"
+
+    # Directory that stores binary files.
+    bin_dir: "bin"
+
+    # Directory that stores Tarantool header files.
+    inc_dir: "include"
+
+    # Path to directory that stores all applications.
+    # The directory can also contain symbolic links to applications.
+    instances_enabled: "instances.enabled"
+
+    # Tarantoolctl artifacts layout compatibility: if set to true tt will not create application
+    # sub-directories for control socket, pid files, log files, etc.. Data files (wal, vinyl,
+    # snap) and multi-instance applications are not affected by this option.
+    tarantoolctl_layout: false
+
+  # Path to file with credentials for downloading Tarantool Enterprise Edition.
+  # credential_path: /path/to/file
+  ee:
+    credential_path: ""
+
+  templates:
+    # The path to templates search directory.
+    - path: "templates"
+
+  repo:
+    # Directory where local rocks files could be found.
+    rocks: ""
+    # Directory that stores installation files.
+    distfiles: "distfiles"