building multi tenant java applications
TRANSCRIPT
Building Multi Tenant Java Applications
Rajesh VenkatesanSenior Architect, HCL [email protected]
Multi Tenancy – An Overview
Inability of SOHO and SMB segments to adopt IT
Non IT Businesses getting entrenched in managing IT
Inability of SOHO and SMB segments to adopt IT
Non IT Businesses getting entrenched in managing IT
Ability to cater to multiple customers using a shared instance of Software/Hardware
Ability to cater to multiple customers using a shared instance of Software/Hardware
That’s what this session is aboutThat’s what this session is about
Time ShareASPEnd User Web
Apps
Time ShareASPEnd User Web
Apps
2
Multi Tenancy Impact in the real world
Single Vs
MultiTenancy
Single Vs
MultiTenancy
3
Architectural Facets of Multi Tenancy inthe Software World
Data Security
Application Security
Standardization of
UI
Data Model
Business Logic
Virtualized Hardware
Database
Application Servers
Inbound
Outbound
Shared Infrastructure
Integration
Configuration over
CustomizationSecurity
4
Typically Multi Tenancy at the database level has 3 standard patterns
Shared Infrastructure – Database
Source: Multi Tenant Data Architecture, Frederick Chong, Gianpaolo Carraro, and Roger Wolter Microsoft Corporation
Separate Database
Traditional – Isolated Database Instance Per Customer
Shared Database Separate Schema
Customers get their own schema but are co-hosted in the same database
Shared Database – Shared Schema
Drives the highest efficiency. All Customers data is stored in the same database and schema with a tenant id qualifier
Isolated SharedShared SchemaSeparate SchemaSeparate DB
Isolated Shared
5
Shared Database – Separate Schema
Shared Database – Shared Schema
Separate Database
Database Multi Tenancy Patterns – Pros and Cons
Trade Off Considerations Compliance/Regulatory
Cost Operations Time to Market
Liability
6
Shared Database Shared Schema
Approach 1
Business Logic and Data Access is aware of multi tenant context and therefore query appropriately
Pros – Easy to build
Cons – High Probability of bugs leading to data leakage
Approach 2
Abstract Multi Tenancy concern to the Data Access Layer and write business logic without tenant context.
Data Access Layer automatically adds tenant context to all data calls
Database Multi Tenancy Implementation
For Hibernate
Use Filters
Use Hibernate Shards
For Hibernate
Use Filters
Use Hibernate Shards
Isolated Database and Shared Database – Separate Schema
Standard Data Access simply returns the appropriate connection based on tenant context
From a JDBC Perspective this implies different connection strings based on the customer.
Typical Tenant Context is set by an intercepting filter and obtained at the DAO layer possibly via a ThreadLocal variable
For Hibernate implement a Tenant aware ConnectionProvider and switch off the second level cache.
From a JDBC Perspective this implies different connection strings based on the customer.
Typical Tenant Context is set by an intercepting filter and obtained at the DAO layer possibly via a ThreadLocal variable
For Hibernate implement a Tenant aware ConnectionProvider and switch off the second level cache.
7
Integration
Typical integration concerns when applications move out of customer premises include
Familiar? SOA?
How can I receive notification
How do I orchestrate my business process
How can I push data to the applicationIs there standard integration
?
? ?
?
8
Inbound Integration
Expose “services”
Technology Independent
Standards Based
High Security
Multi Tenant Aware
Implementation
SOAP
Well Defined StandardWSS for Multi Tenant Security
(Username/Token, X509 –Tenant Certificate, SAML, Kerberos)
REST
Easy IntegrationSimplicitySecurity to be built on top.
Integration – Contd
Axis, XFireAxis, XFire
WSS4JWSS4J
JAX-WSJAX-WS
Fundamentally the application must support well defined interfaces for inbound Integration as well as Outbound Integration
9
Outbound Integration
Allow Tenants to register for integration events.
Push Vs Pull
Push – Synchronous Data can pushed to waiting WS endpoints Publish Standard Web Service Interfaces that customers can implement. Multi Tenant aware integration layer appropriately calls out the tenant specific interface. Problem with availability of customer endpoints
Push Asynchronous Expose Secure Asynchronous Messaging Infrastructure. Heavy Vs Light Weight Events
For security reasons and other reasons, push non-critical information alone into the message. The listening party then calls back via standard web service inbound interface for the actual message.
Push the entire message with all relevant information. The Infrastructure is absolutely secure.
The messaging infrastructure takes responsibility of ensuring delivery.
Integration – Contd
10
Security
Security
Data SecurityApplication Security
Physical Security
Facets of Security
11
Data at Rest
Use tenant specific encryption when required. Decouple encryption awareness from the data layer allowing data leaks to still be harmless TradeOffs
Database functions cannot be applied on encrypted fields Performance
Tokenization of Data – Only a token reference is stored in the database. Actual data has to come from a high security data protection server
Data in Transit
Use Secure means of transfer (https) and add authentication/ authorization layer on top.
Use In Wire Encryption for highly critical data
Data Security
JCA/JCEJCA/JCE
JSSEJSSE
12
Application Security
Application Security is not different from traditional applications but some aspects become a lot more critical.
Exposing the application on the web brings about a gamut of application security threats. Be Aware of possible security vulnerabilities and address them. The OWASP Top Ten Project (http://www.OWASP.org) is a good place to look.
A1: Injection A2: Cross-Site Scripting (XSS) A3: Broken Authentication and Session Management A4: Insecure Direct Object References A5: Cross-Site Request Forgery (CSRF) A6: Security Misconfiguration A7: Insecure Cryptographic Storage A8: Failure to Restrict URL Access A9: Insufficient Transport Layer Protection A10: Unvalidated Redirects and Forwards
13
Application Security – Contd
Some of the security best practices for applications Encrypt all communication between the browser and server via SSL. Strong password policy enforcement using configurable password policy. Passwords are stored after one way encryption in the database. It is impossible to know user
passwords. Auto-Generated Passwords automatically expire after xx hours. Use of token based authentication with zero trust on server side Sessions. All access to the
application is authenticated and is either secured by an authentication token or via certificates. Decoupled Authentication and Authorization and consolidation of concerns in order to establish a
single point of control of user access. RBAC ensuring there are no super-users who get access to the system. Extensive Logging Capability ensuring every action is traceable to the user, request and session
along with the actual change to the database. Database credentials created with named permissions. OS credentials created with named permissions
All Inbound and Outbound interface points must be secured by default. (SSL)
Additional Tenant Aware Security measures like Tenant Specific Certificates
14
Application Security – Federated Identity
With applications moving outside of customer premise, corporate users are forced to have multiple identities one corporate and other in-cloud application identity.
This poses a security problem for customers since a person moving out of the company still has access to corporate data.
Therefore it becomes necessary to allow identity to be federated from the corporate context.
Therefore the application has to be ready to De-Couple Identity Management and Authentication Support delegation of IdM and Authentication to corporate systems through established standards like SAML.
Multi Tenant Application
Corporate LDAPSign In
Tenant 1
Corporate LDAP
Sign In
Tenant n
15
Configuration Over Customization
In order to drive efficiency, an application must standardize its features.
However this results in not being able to accommodate customers with alternate business processes.
This results in an architectural requirement: How to support customization via configuration?
Database Allow extension of existing entities
Business Logic
Business Logic Templates Allow pluggable business logic. Allow small changes to business process
UI
Metadata driven UI Customize
Look and Feel Layout Content
16
UI Customization
Depending on requirements UI customization is done at various depths Look and Feel – The ability to change the font, color and style of existing UI Layout – The ability to switch component layouts Content – The ability to choose what content goes where.
Two Approaches
Both approaches require a metadata layer that can understand the customization done be specific tenants.
UI Rendering must take into account a standard layout as well as the metadata for rendering.
Accommodate tenant specific UI Data models that can extensions to standard data models.
17
Business Process Customization
Enable an application to be flexible in allowing changes to business logic
Allow different workflows to be configured per tenant.
At the application design level Follow a highly de-coupled,
pluggable component based design. Standard IoC Pattern to plug new
implementations
At the functional level Decide on the smaller variations that a
business process/logic can take. Make these configurable.
Allow ability to plugin newer processes as the application evolves.
Accommodate generic data models during processing to cater to extended schemas
Again a metadata layer is required to understand the configuration done by tenants at the business process level as well as newer business process that is available.
Database Customization
Ability to extend the schema as per specific requirement
In the Shared Database – Separate Schema and Separate Database pattern, this becomes trivial as the customization can be done directly.
In the Shared Database-Shared Schema, the following approaches are standard To have a pre-determined set of fields for
specific data models that can be used as extensions.
To have a generic extension schema that can accommodate customization to any entities and a data access and business logic layer that can bring in the tenant context when querying.
Business Logic & Database Customization
SpringSpring
Reference: Multi Tenant Data Architecture,
Frederick Chong, Gianpaolo Carraro, and
Roger WolterMicrosoft Corporation
Reference: Multi Tenant Data Architecture,
Frederick Chong, Gianpaolo Carraro, and
Roger WolterMicrosoft Corporation
18
Scalability
Data
In case of a RDBMS, Shared Database – Shared Schema use partitioning by tenantid (SHARD)
Give a thought about NoSQL Databases if dealing with multiples of TB of data(ACID vs BASE)
Application Server
Clustering Make services as stateless as possible. Session Replication is a nightmare. Avoid file system for data. Use a central datastore
De-Coupled Components Conceptualize application features that can be de-coupled and scaled separately. Allows a resource hogging feature to be separated out and scale strategy planned
differently.
Cache data where possible (memory IS cheap)
Plan for failure – Auto Recovery.
UI
With the current scope of browser capabilities (HTML5) pushing state to the browser has become easier.
Also frameworks like GWT has enabled complex applications to sit on the client side.
For applications using more sophisticated RIA clients (OpenLAZLO, FLEX or Silverlight), the same principle applies
19
Hadoop HBASEHadoop HBASE
Questions?
20