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1
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- A Pure Java Cluster Node
- JAOO 2002
- Michael Ringgaard (mringgaa@csc.com)
- Bjarne Hansen (bhansen4@csc.com)
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2
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- Welcome
- Bjarne Hansen, bhansen4@csc.com
Computer Sciences Corporation
- Michael Ringgaard, mringgaa@csc.com
Computer Sciences Corporation
- Agenda
- What is a jbox?
- Why would we want a jbox?
- What can a jbox be used for?
- How to build a jbox
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3
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- A server appliance for Java programs
- Requires only power and a network connection
- No monitor, keyboard, or mouse
- Built for standard Intel based PC
- Cheap, simple and powerful
- Runs only one process: the Java VM
- Specifically the HotSpot Java VM for Windows
- Relies on a small and efficient kernel
- Transforming application servers to appliances
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4
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- Characteristics of appliances
- Unpack, connect, use...
- Can’t rely on experts to operate ..
- Must require just about zero maintenance
- Like: phone, TV, video, video game, washing machine, oven, ...
- Would be nice characteristics for an IT business system!
- By the way...next generation of home appliances: Broadband router, DHCP,
DNS,...
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5
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- Need effective development and execution platform
- Hardware:
- Before: Exotic processor/hardware
- Now: Complies with PC specification
- Development platform
- Before: C, C like variant, or assembler
- Now: OO, VM, garbage collection
- Cost effective
- Extremely cheap hardware
- Develop on PC, execute on appliance
- Wide selection of development environments, tools, utilities...
- No specialized developers
- Java is a powerful and rich environment yet simple enough to use in an
appliance
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6
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- What would we like to achieve?
- Apply the virtues of traditional appliances to IT business systems
- Apply the effective software development tools, utilities, and
methodologies to appliance development
- As a Java server appliance
- Ideal development environment to develop, deploy and maintain software
for appliances
- As a Java cluster node
- It’s better to own 100 appliances than 100 application servers
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7
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8
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- Clustering support is a feature of specific J2EE server products
- Focus on transparency (developer, user)
- Custom designed distributed architectures
- J2EE +
- Jini, JavaSpaces
- P2P, JXTA, ...
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9
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- Standalone appliances can be managed using browser interface
- Most J2EE servers has built-in web based management consoles
- Appliance clusters requires special attention on deployment and
configuration issues
- How do you deploy applications to many nodes
- Centralized application and configuration repository (JMX).
- Manage applications, not servers
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10
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11
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12
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- What is actually going on under the hood when you run a Java
application?
- How is the JVM using the operating system?
- What features of the operating system are used by a Java server
application?
- Do you really need an operating system?
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13
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- Hardware Abstraction Layer
- Resource Manager
- Bootstrap Loader
- Application Programming Interface
- Virtual Machine Implementation
- Utility Collection
- One-stop-shopping User Entertainment System
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14
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15
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16
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- file
- network
- virtual memory
- threads
- synchronization
- time
- resolver
- heap
- modules
- critical sections
- thread local storage
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17
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18
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- Build a kernel for executing Java server application on appliances
- Use existing HotSpot VM
- Small,simple, fast but complete kernel
- Run on standard PC hardware (IA-32)
- Develop using Microsoft Visual C
- Use standard PE (EXE/DLL) executables
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19
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- Use the existing HotSpot VM
- Write stub DLLs for Win32 DLL
- Implement user mode components:
- loader, heap, tls, critsect, resolver...
- Implement a boot loader to load kernel
- Implement kernel
- memory management, thread control, device I/O and networking.
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20
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- System booting and application loading
- Memory Management
- Virtual memory mapping
- Physical memory allocation and paging
- Heap allocation and module loading and linking
- Thread Control
- Thread scheduling and trap handling
- Thread context
- Thread synchronization and timers
- I/O Management
- I/O bus and unit enumeration
- Block devices and file systems
- Stream devices
- Packet devices (NIC) and networking (TCP/IP)
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21
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- There are lots of information and code on the internet on OS topics:
- Linux kernel code (www.kernel.org)
- IA-32 Reference Manual (www.intel.com)
- TCBs and u-kernels (Jochen Liedtke, i30www.ira.uka.de/teaching/coursedocuments/47/)
- DNS Resolver (ISC BIND lwres, www.isc.org)
- TCP/IP Stack (Adam Dunkels, www.sics.se/~adam/lwip/)
- Heap Allocator (Doug Lea, http://gee.cs.oswego.edu/dl/html/malloc.html)
- Bochs (bochs.sourceforge.net) and WMWare simulators (www.vmware.com)
- IDE Disks (Hale Landis, www.ata-atapi.com)
- ...
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22
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23
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24
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25
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Notes
