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CloudFormation/EC2-访问模板中的 EC2 实例的 IP 地址？

tag-icon • tag-icon amazon-ec2 amazon-web-services amazon-cloudformation
CloudFormation/EC2-访问模板中的 EC2 实例的 IP 地址？

我正在尝试定义一个 Cassandra 节点集群，以及一些其他实例（一些中间件和应用服务器）。我希望能够将 Cassandra 节点的（内部）IP 地址添加到中间件的配置中，并将第一个 Cassandra 节点的 IP 添加到其他节点的配置中，作为种子节点。我可以完全从模板内部实现这一点吗？（在 AMI 中调用脚本是可以的，但集中配置或平台未提供的任何类型的远程数据库则不行）

谢谢！ 安德拉斯

编辑：我忘了提到我还需要使用实例的 IP 来更新相关的安全组。

答案1

在对 AWS 文档进行一番挖掘之后，我发现你可以引用在同一模板中创建的资源的属性，只要它们 a) 在你的引用之前定义 b) 不指向正在创建的资源（没有循环依赖）

b) 意味着要找出 EC2 节点自己的 IP，我确实必须调用 ceejayoz 上面提到的 aws URL

这是我对 Cassandra 节点实例资源的定义。请注意，我在配置文件中放置了标记，以便能够安全地插入正确的值，但您始终可以恢复为简单地替换默认值（例如，将“initial_token: 0”替换为“initial_token: 123”）。

    "Cas1" : {

        "Type" : "AWS::EC2::Instance",
        "Metadata" : {
            "AWS::CloudFormation::Init" : {
                "config" : {
                    "packages" : {
                        "yum" : {
                            "opscenter-free" : [],
                            "pyOpenSSL" : []
                        }
                    }
                },

                "services" : {
                    "sysvinit" : {
                        "cassandra" : {
                            "enabled" : "true",
                            "ensureRunning" : "true"
                        },
                        "opscenterd" : {
                            "enabled" : "true",
                            "ensureRunning" : "true"
                        }
                    }
                }
            }
        },

        "Properties" : {
            "SecurityGroups" : [ { "Ref" : "CommonSecurityGroup" }, { "Ref" : "OpsCenterSecurityGroup" } ],
            "KeyName" : { "Ref" : "KeyName" },
            "InstanceType" : { "Ref" : "CassandraInstanceType" },
            "ImageId" : { "Fn::FindInMap" : [ "AWSRegionArch2AMI", { "Ref" : "AWS::Region" },{ "Fn::FindInMap" : [ "AWSInstanceType2Arch", { "Ref" : "CassandraInstanceType" }, "Arch" ] } ] },
            "UserData" : { "Fn::Base64" : { "Fn::Join" : ["", [
            "#!/bin/bash -v\n",

            "MY_IP=`(curl http://169.254.169.254/latest/meta-data/local-ipv4)`\n",
            "sed -i 's/REPLACE_WITH_TOKEN/0/g' /etc/cassandra/conf/cassandra.yaml\n",
            "sed -i 's/REPLACE_WITH_MY_IP/'$MY_IP'/g' /etc/cassandra/conf/cassandra.yaml\n",
            "sed -i 's/REPLACE_WITH_SEED_IP/'$MY_IP'/g' /etc/cassandra/conf/cassandra.yaml\n",
            "sed -i 's/REPLACE_WITH_MAX_HEAP_SIZE/8G/g' /etc/cassandra/conf/cassandra-env.sh\n",
            "sed -i 's/REPLACE_WITH_HEAP_NEWSIZE/4G/g' /etc/cassandra/conf/cassandra-env.sh\n",

            "yum update -y aws-cfn-bootstrap\n",

            "/opt/aws/bin/cfn-init -s ", { "Ref" : "AWS::StackName" }, " -r Cas1 ",
            "    --access-key ",  { "Ref" : "HostKeys" },
            "    --secret-key ", {"Fn::GetAtt": ["HostKeys", "SecretAccessKey"]},
            "    --region ", { "Ref" : "AWS::Region" }, " || error_exit 'Failed to run cfn-init'\n",

            "sed -i 's/127.0.0.1/'$MY_IP'/g' /etc/opscenter/opscenterd.conf\n",
            "sed -i 's/#passwd_file/passwd_file/g' /etc/opscenter/opscenterd.conf\n",
            "echo 'xxx:xxx:admin' > /etc/opscenter/.passwd\n",

            "rm -fR /var/lib/cassandra/data\n",
            "rm -fR /var/lib/cassandra/commitlog\n",
            "mkdir /var/lib/cassandra/data\n",
            "mkdir /var/lib/cassandra/commitlog\n",
            "chown -R cassandra:cassandra /var/lib/cassandra\n",

            "service cassandra start\n",
            "service opscenterd start\n"

            ]]}}
        }

    },

后续节点的配置相同，除了行

            "sed -i 's/REPLACE_WITH_SEED_IP/'$MY_IP'/g' /etc/cassandra/conf/cassandra.yaml\n",

引用种子（第一个）节点的 IP 地址

            "sed -i 's/REPLACE_WITH_SEED_IP/", { "Fn::GetAtt" : ["Cas1", "PrivateIp"] }, "/g' /etc/cassandra/conf/cassandra.yaml\n",

至于将实例 IP 添加到安全组，这似乎是不必要的，您只需创建一个组并向其中添加 Ingress 资源，并在其中引用该组作为源

    "CommonSecurityGroup" : {
        "Type" : "AWS::EC2::SecurityGroup",
        "Properties" : {
            "GroupDescription" : "Enables",
            "SecurityGroupIngress" : [ {
                "IpProtocol" : "tcp",
                "FromPort" : "22",
                "ToPort" : "22",
                "CidrIp" : "0.0.0.0/0"
            } ]
        }
    },

    "OpsCenterSecurityGroup" : {
        "Type" : "AWS::EC2::SecurityGroup",
        "Properties" : {
            "GroupDescription" : "Enables",
            "SecurityGroupIngress" : [ {
                "IpProtocol" : "tcp",
                "FromPort" : "8888",
                "ToPort" : "8888",
                "CidrIp" : "0.0.0.0/0"
            },
            "SecurityGroupIngress" : [ {
                "IpProtocol" : "tcp",
                "FromPort" : "61620",
                "ToPort" : "61621",
                "SourceSecurityGroupName" : { "Ref": "CommonSecurityGroup" }
            } ]
        }
    },

    "CassandraThriftIngress" : {
        "Type" : "AWS::EC2::SecurityGroupIngress",
        "Properties" : {
            "GroupName": { "Ref": "CommonSecurityGroup" },
            "IpProtocol" : "tcp",
            "FromPort" : "9160",
            "ToPort" : "9160",
            "SourceSecurityGroupName" : { "Ref": "CommonSecurityGroup" }
        }
    },

    "CassandraData" : {
        "Type" : "AWS::EC2::SecurityGroupIngress",
        "Properties" : {
            "GroupName": { "Ref": "CommonSecurityGroup" },
            "IpProtocol" : "tcp",
            "FromPort" : "7000",
            "ToPort" : "7001",
            "SourceSecurityGroupName" : { "Ref": "CommonSecurityGroup" }
        }
    },

    "CassandraJMX" : {
        "Type" : "AWS::EC2::SecurityGroupIngress",
        "Properties" : {
            "GroupName": { "Ref": "CommonSecurityGroup" },
            "IpProtocol" : "tcp",
            "FromPort" : "7199",
            "ToPort" : "7199",
            "SourceSecurityGroupName" : { "Ref": "OpsCenterSecurityGroup" }
        }
    },

答案2

可以调用 AMI 中的脚本

如果是这样，您只需要 cURL 和 EC2 的内部元数据服务。从实例中：

curl http://169.254.169.254/latest/meta-data/local-ipv4

还有一大堆其他可用的元数据http://169.254.169.254/latest/meta-data/——主机名、安全组、实例 ID 等。

答案3

是的，您可以完全在模板内完成此操作。下面是模板的“资源”部分，其中定义了三个实例：两个 Cassandra 实例和一个中间件实例。

第二个 Cassandra 实例接收第一个 Cassandra 实例的 IP 作为用户数据。中间件实例接收两个 Cassandra 实例的 IP，也将其作为用户数据。

两个 Cassandra 实例都添加到“cassandra-nodes”安全组中。我没有包含此定义，但在片段部分。您不需要手动将其 IP 添加到 SG，只需在描述实例时引用它即可。

"Resources" : {
    "CassOneInstance" : {
      "Type" : "AWS::EC2::Instance",
      "Properties" : {
        "ImageId" : "ami-123",
        "InstanceType": "c1.medium",
        "SecurityGroups" : [ "cassandra-nodes" ]
      }
    },
    "CassTwoInstance" : {
      "Type" : "AWS::EC2::Instance",
      "Properties" : {
        "ImageId" : "ami-123",
        "InstanceType": "c1.medium",
        "SecurityGroups" : [ "cassandra-nodes" ],
        "UserData" : { 
            "Fn::Base64" : { 
                "Fn::Join" : [ ":", [ 
                    { "Fn::GetAtt" : [ "CaseOneInstance", "PrivateIP" ] }
                ] 
            }
         },
      }
    },
    "MiddleWareInstance" : {
      "Type" : "AWS::EC2::Instance",
      "Properties" : {
        "ImageId" : "ami-123",
        "InstanceType": "c1.medium",
        "UserData" : { 
            "Fn::Base64" : { 
                "Fn::Join" : [ ":", [ 
                    { "Fn::GetAtt" : [ "CaseOneInstance", "PrivateIp" ] },
                    { "Fn::GetAtt" : [ "CaseTwoInstance", "PrivateIp" ] }
                ]
            }
         },
      }
    }
}

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