テストのために、3 ノード クラスターを 2 ノードに縮小し、後で 5 ノード クラスターに対して同じことを実行したいと考えました。
ただし、クラスターを縮小するベスト プラクティスに従うと、次のようになります。
- すべてのテーブルをバックアップする
- すべてのテーブル:
alter table xyz set (number_of_replicas=2)以前は 2 未満だった場合SET GLOBAL PERSISTENT discovery.zen.minimum_master_nodes = <half of the cluster + 1>;
3a。データ チェックが常に緑色である必要がある場合は、min_availability を「full」に設定します: https://crate.io/docs/reference/configuration.html#graceful-stop- 1 つのノードでグレースフル ストップを開始する
- データチェックが緑色になるまで待ちます
- 3から繰り返します。
- 完了したら、次のノード構成を永続化します
crate.yml。gateway.recover_after_nodes: n discovery.zen.minimum_master_nodes:[![enter image description here][1]][1] (n/2) +1 gateway.expected_nodes: n
クラスターが再び「グリーン」に戻ることはなく、重要なノードのチェックも失敗しています。
ここで何がうまくいかなかったのですか？
crate.yml:
...
################################## Discovery ##################################
# Discovery infrastructure ensures nodes can be found within a cluster
# and master node is elected. Multicast discovery is the default.
# Set to ensure a node sees M other master eligible nodes to be considered
# operational within the cluster. Its recommended to set it to a higher value
# than 1 when running more than 2 nodes in the cluster.
#
# We highly recommend to set the minimum master nodes as follows:
# minimum_master_nodes: (N / 2) + 1 where N is the cluster size
# That will ensure a full recovery of the cluster state.
#
discovery.zen.minimum_master_nodes: 2
# Set the time to wait for ping responses from other nodes when discovering.
# Set this option to a higher value on a slow or congested network
# to minimize discovery failures:
#
# discovery.zen.ping.timeout: 3s
#
# Time a node is waiting for responses from other nodes to a published
# cluster state.
#
# discovery.zen.publish_timeout: 30s
# Unicast discovery allows to explicitly control which nodes will be used
# to discover the cluster. It can be used when multicast is not present,
# or to restrict the cluster communication-wise.
# For example, Amazon Web Services doesn't support multicast discovery.
# Therefore, you need to specify the instances you want to connect to a
# cluster as described in the following steps:
#
# 1. Disable multicast discovery (enabled by default):
#
discovery.zen.ping.multicast.enabled: false
#
# 2. Configure an initial list of master nodes in the cluster
# to perform discovery when new nodes (master or data) are started:
#
# If you want to debug the discovery process, you can set a logger in
# 'config/logging.yml' to help you doing so.
#
################################### Gateway ###################################
# The gateway persists cluster meta data on disk every time the meta data
# changes. This data is stored persistently across full cluster restarts
# and recovered after nodes are started again.
# Defines the number of nodes that need to be started before any cluster
# state recovery will start.
#
gateway.recover_after_nodes: 3
# Defines the time to wait before starting the recovery once the number
# of nodes defined in gateway.recover_after_nodes are started.
#
#gateway.recover_after_time: 5m
# Defines how many nodes should be waited for until the cluster state is
# recovered immediately. The value should be equal to the number of nodes
# in the cluster.
#
gateway.expected_nodes: 3