Making Tomcat Multi-tenant, Elastic, Billed
and Metered
Paul Fremantle
CTO and Co-Founder, WSO2
VP, Apache Synapse
ASF Member
@pzfreo
http://pzf.fremantle.org
Afhkam Azeez
Lead Architect, Stratos
Axis2, Synapse PMC
ASF Member
And also big thanks to Shankar, Amila, Srinath, Isuru,
Senaka and the whole team
Paul Fremantle
• Working in Apache
since 2002
• Apache Member
• CTO and Co-Founder of
WSO2
• VP, Apache Synapse
• I play the Tin Whistle
(in case you hadn’t
noticed yet)
@tedleung
Ok I lied a bit
• This is about “Using Tomcat to run multitenanted, metered, elastic webapps”
• We didn’t embed this into Tomcat code
• If you want to leave now, I won’t be
offended!
“Cloud Native”
•
•
•
•
•
•
Self-service
Distributed and Elastic
Multi-tenant
Metered and Billed
Dynamically wired
Versionable, incrementally deployable and
testable
http://www.flickr.com/photos/ladymaggic/
http://www.flickr.com/photos/jurvetson/
Can I run Tomcat on the Cloud?
• Yes of course
• There is at least one company selling
supported AMI images of Tomcat
• What does that get me?
– Saves me creating an AMI
• Can we do better? Yes!
Cloud computing in one page
The Big Picture
• Infrastructure as a Service
– Servers, storage & networking
– For infrastructure specialists
• Platform as a Service
– Middleware and Core Services
– For developers, integrators, architects
• Software as a Service
– Applications
– For end-users
Enterprise IT in 2010
© WSO2 2010
9
Enterprise IT in 2015+
© WSO2 2010
10
Stratos Application Server
What can I do with Stratos App Server?
• Deploy WAR files
• Manage sessions
– Monitor
– Expire
• Reload / Stop
A webapp, running in the cloud
Quick demo
Not just webapps – services too
• Supports deploying code as services
–
–
–
–
JAX-WS
Axis2 services
POJO
Spring-based POJO services
Uses Tomcat
•
•
•
•
Running on Tomcat under OSGi
Multi-tenant
Metered
Elastic
How?
• How do we multi-tenant?
• How do we meter?
• How do we scale (elasticity)?
What Multi-tenancy ?

Many Parties shared same set of resources,
while giving each an his own space
Challenges of Multi-tenancy
• Security and Data Isolation
• Allocation of resources
• Configuration, Management
• Programming Model
Multi-tenanting Tomcat
• http://appserver.cloud.wso2.com/t/fremantle.org/webapps
/sample/
• Uses a valve to direct the request to the right tenant
• WAR files already have separate classloaders
– And session isolation
• Each tenant can only load code from their tenants deployed
WARs
• For services we also restrict classloading using Java Security
• We apply security policies to stop webapps opening ports,
modifying local files, calling OSGi Services
– We intend to enhance this to support limited access to services
Multi-tenanting Axis2
Every tenant has access to an Identity Service
Identity
• Every domain/tenant has its own single-sign
on and identity manager
• Based on LDAP – which is inherently multitenant
– Each tenant has their own LDAP partition
• Supporting SAML2, OpenId, OAuth, XACML,
Infocard, WS-Trust
Simply enabling security
<security-constraint>
<display-name>Example Security Constraint</display-name>
<web-resource-collection>
<!– some stuff deleted for simplicity-->
<login-config>
<auth-method>FORM</auth-method>
<realm-name>Example Form-Based Authentication Area</realm-name>
<form-login-config>
<form-login-page>/login.jsp</form-login-page>
<form-error-page>/login-error.jsp</form-error-page>
</form-login-config>
</login-config>
<!-- Security roles referenced by this web application -->
<security-role>
<role-name>admin</role-name>
</security-role>
Single sign-on
• We already support SAML2 based single-sign on for
Administration
– So if you want, you can use a SAML2 Relying Party in
your webapp, that works
– We can recommend one too
• OpenSAML2
• https://spaces.internet2.edu/display/OpenSAML/Home/
• Not yet automatically supported for webapps
– We plan to add this
Elasticity
• Elastic Load Balancer
– Apache Synapse
• Always done load balancing
• Now has full transparent HTTP support
• Has “Autoscale” mediators
– Based on Azeez’s Master’s thesis
• Priority Execution support and throttling (Business
Class)
– Underlying Cloud API
• We have based on Amazon/Eucalyptus/Ubuntu API
• Adding support for vmWare underneath
Overall plan
Apache Tribes
Distributed
• Our distribution/clustering model is based
on Apache Tribes
• Adjusted Tribes to support WKA model
• In a large cloud (e.g. Amazon) you cannot
rely on subnet communications between
nodes
• Nominate two Well Known Addresses
– Tribes contacts the WKA and uses that the
bootstrap the fabric
Performance Overhead of Multi-tenancy
Metering
Super tenant metering
Billing and Metering
• A generic multi-tenanted metering and
billing module
• Written as OSGi
• Uses Drools to implement service levels
– E.g. 10 users, 100Mb transfer/month, 15
deployed services for free level of subscription
• Can be used to meter real business events
– How many sales transactions / month
Programming Model
• Sub-tenant programming model
– “Normal”
– Suited to fit within a tenant
• Super-tenant model
– How to write one app for all tenants
– i.e. how to write multi-tenant apps
– Different but similar
• Neither is complete yet
Data
• Is a pain
• Most webapps use JDBC-based data sources
– Very hard to “multi-tenant”
• We are looking at two options:
– Multi-tenanted JBDC driver
– Multi-tenant NoSQL (e.g. Cassandra)
• In Amazon environment you can start up RDS
– But you pay for time not usage
Cache
• Uses JSR107
• cache =
CarbonContext.getCurrentContext().getCache();
• cache.put(key, value);
• value = cache.get(key);
• CarbonContext is our general model for building a
sub-tenant multi-tenant programming model
– A set of standard stuff that works in an MT environment
– Isolation and security
What else do you need?
• Multi-tenant enabled:
–
–
–
–
–
–
–
–
Log
Cache (done)
Billing
Identity
Authorization
JMS/Queue/Topics
Registry/Repository/Config access
Managed Service Requester (HTTP, SOAP)
• JAXWS/JAXRS/Commons HTTPClient
Summary
• Cloud Native attributes distinguish code that
just floats on top of the cloud from
applications that live in the cloud
• Stratos is an example of a making Tomcat
Cloud Native
• Not complete…. But that would be boring
anyway!