1. TOSCA Workflows
Use Cases

2. Concurrency resolving
tomcat
Tomcat
Requirements
Host
Scenario 1:
Create operation download zip files and unzip them,
both in parallel in order to optimize bandwidth.
HostedOn
mysql
MySQL
Requirements
Host
compute started
mysql creating
tomcat creating
mysql create
tomcat create
HostedOn
compute
tosca.nodes.Compute
Capabilities
Container
mysql created
tomcat created

3. Concurrency resolving
tomcat
Tomcat
Requirements
Host
compute started
Scenario 2:
Create operation performed through apt-get command that doesn’t support concurrency.
mysql creating
HostedOn
mysql
MySQL
Requirements
Host
mysql create
mysql created
tomcat creating
HostedOn
tomcat create
compute
tosca.nodes.Compute
Capabilities
Container
tomcat created

4. Hosted_On – Active hosting
compute started
tomcat creating
Note: pre_configure_target and post_configure_target operations are not allowed as the compte node is not provided by the user but Substituated by the orchestrator.
The user has no ownership on it’s lifecycle.
tomcat create
tomcat
Tomcat
Capabilities
Container
Requirements
Host
tomcat created
tomcat configuring
HostedOn pre_configure_source
tomcat configure
HostedOn post_configure_source
HostedOn
compute
tosca.nodes.Compute
Capabilities
Container
tomcat configured
tomcat starting
tomcat start
tomcat started
Many other scenaris like Database on DBMS, even some War on containers

5. Hosted_On – Passive hosting
Source
ElasticSearch Plugin
Requirements
Host
I need to create the plugin before the ElasticSearch is created
HostedOn
Target
ElasticSearch
Capabilities
Container
ElasticSearch Java plugins: Documentation extract:
These plugins contain only JAR files, and must be installed on every node in the cluster. After installation, each node must be restarted before the plugin becomes visible.

6. Cluster Manager/Managed use case
Need some nodes to be in certain states before next nodes do something.
Cluster with master Election and then need the address of the master
Runtime impacts with new master election are also to consider.
TODO detail the use-case