Terraform Aws RDS parameter group 適用時エラー

TerrafromでAWS RDS作成時にDBパラメーターグループにパラメーターを指定してTerraform apply実行すると以下のエラーが出たりします。

sample .tf file

# Create parameter group for mariadb
resource "aws_db_parameter_group" "db-pg" {
    name = "test-mariadb10-1"
    family = "mariadb10.1"
    description = "mariadb parameter group for test project"

    parameter {
        name = "character-set-client-handshake"
        value = "0"
    }
    parameter {
        name = "character_set_client"
        value = "utf8"
    }
    parameter {
        name = "character_set_connection"
        value = "utf8"
    }
    parameter {
        name = "character_set_database"
        value = "utf8"
    }
    parameter {
        name = "character_set_results"
        value = "utf8"
    }
    parameter {
        name = "character_set_server"
        value = "utf8"
    }
    parameter {
        name = "log_bin_trust_function_creators"
        value = "1"
    }
    parameter {
        name = "max_allowed_packet"
        value = "10240000"
    }
    parameter {
        name = "skip-character-set-client-handshake"
        value = "1"
    }
}

terraform apply error

Error modifying DB Parameter Group: InvalidParameterCombination: cannot use immediate apply method for static parameter status code: 400

原因

DB再起動しないと適用できないパラメータの場合は、すぐ適用できないため、失敗する

解決策

apply_methodの値をpending-rebootに設定する。デフォルトではImmediateになっている

# Create parameter group for mariadb
resource "aws_db_parameter_group" "gmaridb-pg" {
    name = "test-mariadb10-1"
    family = "mariadb10.1"
    description = "mariadb parameter group for test project"

    parameter {
        name = "character-set-client-handshake"
        value = "0"
        //default is immediate
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "character_set_client"
        value = "utf8"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "character_set_connection"
        value = "utf8"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "character_set_database"
        value = "utf8"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "character_set_results"
        value = "utf8"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "character_set_server"
        value = "utf8"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "log_bin_trust_function_creators"
        value = "1"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "max_allowed_packet"
        value = "10240000"
        apply_method = "pending-reboot" 
    }
    parameter {
        name = "skip-character-set-client-handshake"
        value = "1"
        apply_method = "pending-reboot" 
    }
}