docker - 在Docker-compose完成后填充cassandra

Question

这是我的docker-compose.yaml:

version: '3'
services:
  cassandra:
    container_name: cassandra
    image: cassandra:3.10
    ports:
      - 9142:9042
    volumes:
      - $PWD/src/database/migrations:/migrations
    depends_on:
      - mysql
  mysql:
    image: mysql:5.7
    volumes:
      - ./src/database/migrations:/docker-entrypoint-initdb.d
    ports:
      - 3307:3306
    restart: always
    environment:
      - MYSQL_ROOT_PASSWORD=password
      - MYSQL_DATABASE=leonardo
      - MYSQL_ALLOW_EMPTY_PASSWORD=1

和一个shell脚本 bootstrap.sh开始:

#!/bin/bash
set -e
docker-compose -f $PWD/docker-compose.yaml down
docker-compose -f $PWD/docker-compose.yaml up -d

这正在工作并启动堆栈。
现在，我想向Cassandra添加一个键空间，但是，在此行下面抛出一个错误:

docker-compose -f $PWD/docker-compose.yaml exec cassandra /bin/sh -c $'cqlsh cassandra -e "CREATE KEYSPACE mykeyspace WITH replication = {\'class\': \'SimpleStrategy\', \'replication_factor\': \'1\'}  AND durable_writes = true;"'

Connection error: ('Unable to connect to any servers', {'172.18.0.2': error(111, "Tried connecting to [('172.18.0.2', 9042)]. Last error: Connection refused")})

Cassandra可能尚未初始化。
有什么好的方法呢？

Answer 1

如果在启动容器后立即尝试在bootstrap.sh脚本中的Cassandra中执行命令，则Cassandra服务器将没有时间启动。

一个简单的解决方案是使用until loop在脚本中等待几秒钟后再执行命令:

#!/bin/bash
set -e
docker-compose -f $PWD/docker-compose.yaml down
docker-compose -f $PWD/docker-compose.yaml up -d
until docker-compose -f $PWD/docker-compose.yaml exec cassandra /bin/sh -c "cqlsh cassandra -e 'show version'";
do
  docker-compose -f $PWD/docker-compose.yaml exec cassandra /bin/sh -c $'cqlsh cassandra -e "CREATE KEYSPACE mykeyspace WITH replication = {\'class\': \'SimpleStrategy\', \'replication_factor\': \'1\'}  AND durable_writes = true;"'
done