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文章目錄
TOSCA（Topology and Orchestration Specification for Cloud Applications）是由OASIS組織制定的云應用拓撲編排規(guī)范。通俗地說，就是制定了一個標準，用來描述云平臺上應用的拓撲結(jié)構(gòu)。目前支持XML和YAML，Cloudiy的藍圖就是基于這個規(guī)范而來。這個規(guī)范比較龐大，本文盡量濃縮了TOSCA的YAML版前兩章，以便用盡量少的時間了解盡量多的規(guī)范內(nèi)容。 簡介TOSCA的基本概念只有兩個：節(jié)點（node）和關(guān)系（relationship）。節(jié)點有許多類型，可以是一臺服務器，一個網(wǎng)絡，一個計算節(jié)點等等。關(guān)系描述了節(jié)點之間是如何連接的。舉個栗子：一個nodejs應用（節(jié)點）部署在（關(guān)系）名為host的主機（節(jié)點）上。節(jié)點和關(guān)系都可以通過程序來擴展和實現(xiàn)。 目前它的開源實現(xiàn)有OpenStack (Heat-Translator，Tacker，Senlin)，Alien4Cloud，Cloudify等。 示例Hello World首先登場的是廣大程序猿和攻城獅們都喜聞樂見的Hello World，但是其實里面并沒有Hello World，只是比較簡單而已。先看下面這段描述文件： tosca_definitions_version: tosca_simple_yaml_1_0
description: Template for deploying a single server with predefined properties.
topology_template:
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
num_cpus: 1
disk_size: 10 GB
mem_size: 4096 MB
os:
properties:
architecture: x86_64
type: linux
distribution: rhel
version: 6.5
除了TOSCA的版本 輸入輸出再看看下面這個描述文件： topology_template:
inputs:
cpus:
type: integer
description: Number of CPUs for the server.
constraints:
- valid_values: [ 1, 2, 4, 8 ]
node_templates:
my_server:
type: tosca.nodes.Compute
capabilities:
host:
properties:
num_cpus: { get_input: cpus }
mem_size: 2048 MB
disk_size: 10 GB
outputs:
server_ip:
description: The private IP address of the provisioned server.
value: { get_attribute: [ my_server, private_address ] }
這里的 安裝軟件第三個描述文件如下： topology_template:
inputs:
# 略
node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: { get_input: my_mysql_rootpw }
port: { get_input: my_mysql_port }
requirements:
- host: db_server
db_server:
type: tosca.nodes.Compute
capabilities:
# 略
我們看到了一個新的節(jié)點類型： 初始化數(shù)據(jù)庫第四個描述文件如下： node_templates:
my_db:
type: tosca.nodes.Database.MySQL
properties:
name: { get_input: database_name }
user: { get_input: database_user }
password: { get_input: database_password }
port: { get_input: database_port }
artifacts:
db_content:
file: files/my_db_content.txt
type: tosca.artifacts.File
requirements:
- host: mysql
interfaces:
Standard:
create:
implementation: db_create.sh
inputs:
db_data: { get_artifact: [ SELF, db_content ] }
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
root_password: { get_input: mysql_rootpw }
port: { get_input: mysql_port }
requirements:
- host: db_server
db_server:
# 略
這里的 兩層應用再來看看第五個描述文件： node_templates:
wordpress:
type: tosca.nodes.WebApplication.WordPress
properties:
context_root: { get_input: context_root }
admin_user: { get_input: wp_admin_username }
admin_password: { get_input: wp_admin_password }
db_host: { get_attribute: [ db_server, private_address ] }
requirements:
- host: apache
- database_endpoint: wordpress_db
interfaces:
Standard:
inputs:
db_host: { get_attribute: [ db_server, private_address ] }
db_port: { get_property: [ wordpress_db, port ] }
db_name: { get_property: [ wordpress_db, name ] }
db_user: { get_property: [ wordpress_db, user ] }
db_password: { get_property: [ wordpress_db, password ] }
apache:
type: tosca.nodes.WebServer.Apache
properties:
# 略
requirements:
- host: web_server
web_server:
type: tosca.nodes.Compute
# 略
wordpress_db:
type: tosca.nodes.Database.MySQL
# 略
mysql:
type: tosca.nodes.DBMS.MySQL
# 略
db_server:
type: tosca.nodes.Compute
# 略
這個文件描述了一個很常見的拓撲結(jié)構(gòu)： 關(guān)系定制化第六個描述文件： node_templates:
wordpress:
type: tosca.nodes.WebApplication.WordPress
properties:
# 略
requirements:
- host: apache
- database_endpoint:
node: wordpress_db
relationship: my.types.WordpressDbConnection
wordpress_db:
type: tosca.nodes.Database.MySQL
properties:
# 略
requirements:
- host: mysql
relationship_templates:
my.types.WordpressDbConnection:
type: ConnectsTo
interfaces:
Configure:
pre_configure_source: scripts/wp_db_configure.sh
這里的關(guān)注點是 tosca_definitions_version: tosca_simple_yaml_1_0
description: Definition of custom WordpressDbConnection relationship type
relationship_types:
my.types.WordpressDbConnection:
derived_from: tosca.relationships.ConnectsTo
interfaces:
Configure:
pre_configure_source: scripts/wp_db_configure.sh
限定需求資源再看一個描述文件： node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
# 略
requirements:
- host:
node_filter:
capabilities:
- host:
properties:
- num_cpus: { in_range: [ 1, 4 ] }
- mem_size: { greater_or_equal: 2 GB }
- os:
properties:
- architecture: { equal: x86_64 }
- type: linux
- distribution: ubuntu
需要關(guān)注的是 node_templates:
mysql:
type: tosca.nodes.DBMS.MySQL
properties:
# 略
requirements:
- host: mysql_compute
mysql_compute:
type: Compute
node_filter:
capabilities:
- host:
properties:
num_cpus: { equal: 2 }
mem_size: { greater_or_equal: 2 GB }
- os:
properties:
architecture: { equal: x86_64 }
type: linux
distribution: ubuntu
數(shù)據(jù)庫也可以使用： node_templates:
my_app:
type: my.types.MyApplication
properties:
admin_user: { get_input: admin_username }
admin_password: { get_input: admin_password }
db_endpoint_url: { get_property: [SELF, database_endpoint, url_path ] }
requirements:
- database_endpoint:
node: my.types.nodes.MyDatabase
node_filter:
properties:
- db_version: { greater_or_equal: 5.5 }
上面指定了數(shù)據(jù)庫的版本。也可以抽出來做個模板： node_templates:
my_app:
type: my.types.MyApplication
properties:
admin_user: { get_input: admin_username }
admin_password: { get_input: admin_password }
db_endpoint_url: { get_property: [SELF, database_endpoint, url_path ] }
requirements:
- database_endpoint: my_abstract_database
my_abstract_database:
type: my.types.nodes.MyDatabase
properties:
- db_version: { greater_or_equal: 5.5 }
節(jié)點模板替換再看一個描述文件： node_templates:
web_app:
type: tosca.nodes.WebApplication.MyWebApp
requirements:
- host: web_server
- database_endpoint: db
web_server:
type: tosca.nodes.WebServer
requirements:
- host: server
server:
type: tosca.nodes.Compute
# 略
db:
# 這是一個抽象節(jié)點
type: tosca.nodes.Database
properties:
user: my_db_user
password: secret
name: my_db_name
這里的 topology_template:
inputs:
db_user:
type: string
# 略
substitution_mappings:
node_type: tosca.nodes.Database
capabilities:
database_endpoint: [ database, database_endpoint ]
node_templates:
database:
type: tosca.nodes.Database
properties:
user: { get_input: db_user }
# 略
requirements:
- host: dbms
dbms:
type: tosca.nodes.DBMS
# 略
server:
type: tosca.nodes.Compute
# 略
這里的 節(jié)點模板組再看一個描述文件： node_templates:
apache:
type: tosca.nodes.WebServer.Apache
properties:
# 略
requirements:
- host: server
server:
type: tosca.nodes.Compute
# 略
groups:
webserver_group:
type: tosca.groups.Root
members: [ apache, server ]
policies:
- my_anti_collocation_policy:
type: my.policies.anticolocateion
targets: [ webserver_group ]
# 可以一起處理
這個例子表明了 YAML宏下面這個描述文件使用了宏來避免重復： dsl_definitions:
my_compute_node_props: &my_compute_node_props
disk_size: 10 GB
num_cpus: 1
mem_size: 2 GB
topology_template:
node_templates:
my_server:
type: Compute
capabilities:
- host:
properties: *my_compute_node_props
my_database:
type: Compute
capabilities:
- host:
properties: *my_compute_node_props
傳參先看一個描述文件： node_templates:
wordpress:
type: tosca.nodes.WebApplication.WordPress
requirements:
- database_endpoint: mysql_database
interfaces:
Standard:
inputs:
wp_db_port: { get_property: [ SELF, database_endpoint, port ] }
configure:
implementation: wordpress_configure.sh
inputs:
wp_db_port: { get_property: [ SELF, database_endpoint, port ] }
這個例子有兩個 node_templates:
frontend:
type: MyTypes.SomeNodeType
attributes:
url: { get_operation_output: [ SELF, Standard, create, generated_url ] }
interfaces:
Standard:
create:
implementation: scripts/frontend/create.sh
configure:
implementation: scripts/frontend/configure.sh
inputs:
data_dir: { get_operation_output: [ SELF, Standard, create, data_dir ] }
在這個例子里有兩個 取動態(tài)值最后一個描述文件： node_types:
ServerNode:
derived_from: SoftwareComponent
properties:
notification_port:
type: integer
capabilities:
# 略
ClientNode:
derived_from: SoftwareComponent
properties:
# 略
requirements:
- server:
capability: Endpoint
node: ServerNode
relationship: ConnectsTo
topology_template:
node_templates:
my_server:
type: ServerNode
properties:
notification_port: 8000
my_client:
type: ClientNode
requirements:
- server:
node: my_server
relationship: my_connection
relationship_templates:
my_connection:
type: ConnectsTo
interfaces:
Configure:
inputs:
targ_notify_port: { get_attribute: [ TARGET, notification_port ] }
# 略
這個例子里，類型為 |
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