Distributed Systems

Distributed Systems

CPSC 416, Winter 2018

Mon/Wed/Fri 3-4:00PM, HDP 310, UBC course page

Course piazza

Office hours:
Matthew... Mon 16:00-17:00 (X151)
Renato.... Tue 15:00-16:00 (X151)
Gleb........ Wed 13:00-14:00 (X151)
Anna....... Thu 13:00-14:00 (X239)
Ivan......... Fri 10:00-11:00 (ICICS 327)


Course description

Leslie Lamport, a computer scientist who won the 2013 ACM Turing Award, gave the following definition of a distributed system:

A distributed system is one in which the failure of a computer you didn't even know existed can render your own computer unusable.

Yet, distribution provides numerous benefits. A system becomes more fault tolerant if there are fewer points of failure and it has no centralized components. By extending the system with more physical nodes the system gains performance and becomes more scalable, capable of handling more load. Distribution can also improve latency, by improving geographic diversity, by placing resources closer to clients who use the system.

Achieving these benefits is not easy. As the quote above illustrates, distributed systems can fail in complex ways and these systems are more difficult to build, test, and understand than centralized systems.

This course will introduce you to a broad range of topics in distributed systems. The tentative topics are listed in the schedule below. For the most part this will be a lecture-style course. However, distributed system concepts are notoriously challenging to internalize without first-hand experience. The emphasis of this course, therefore, will be on building distributed system prototypes, small and large.

Course pre-requisites: CPSC 317 (networks) and CPSC 313 (computer hardware and operating systems).

Course staff: Ivan Beschastnikh (Instructor), Renato Costa (TA), Matthew Do (TA), Gleb Naumenko (TA), Anna Zheltukhina (TA).

Go programming language

In this course we will exclusively use the Go programming language for all assignments. Learning a new programming language is an important skill. You will practice it in this course. For the most part I will expect that you learn this language on your own.

Amanda and Stewart led an in-class Go tutorial in Winter 2017 version of the course. Here is the recorded version: part 1, and part 2.

Textbooks

There are three optional books for this course:

  1. Go Programming Language
  2. Programming in Go
  3. Distributed Systems: Principles and Paradigms (2nd Edition)
Although there are many tutorials introducing Go and the online Go documentation is well developed, some of you may find the first two books on the list helpful for a step-by-step introduction to Go.

Communication

Use the course Piazza for all course-related communication. The Piazza also supports private posts that you can use to communicate with the instructor and the TAs.

Course-level learning goals

The course will provide an opportunity for participants to

  • understand key principles in designing and implementing distributed systems
  • reason about problems that involve distributed components
  • become familiar with important techniques for solving problems that arise in distributed contexts
  • build distributed system prototypes using the Go programming language

Schedule (a work in progress)

Jan 3
Wed
Introduction and course overview [slides]

Read through Go resources prior to class, and practice as much Go as you can.

Jan 5
Fri
Assignment 1 overview and networking 1/2 [slides]
Jan 8
Mon
Networking 1/2 continued: network stack, routing [slides]
Jan 10
Wed
Networking 2/2 continued: fate sharing, e2e arguments, start of RPC [slides]
Jan 12
Fri
RPC [slides]
Jan 15
Mon
Assignment 1 due
Assignment 2 overview
Jan 17
Wed
Assignment 2 solution sketch and edge-cases review
Jan 19
Fri
Distributed file systems overview: NFS and AFS [slides]
Jan 22
Mon
Client-side caching, caching in NFS [slides]
Jan 24
Wed
Caching in AFS, dist. FS semantics (e.g., session semantics) [slides]
Jan 26
Fri
Distributed P2P ledger: BitCoin [See last year notes]
Jan 29
Mon
Project 1 posted [in-class notes]
Assignment 2 due
Jan 31
Wed
Peer to peer systems [slides]
Feb 2
Fri
Time synchronization [slides]
Feb 5
Mon
Logical time [Lamport and vector clocks] [slides]
Feb 7
Wed
Distributed mutual exclusion [slides]
Feb 9
Fri
Fault Tolerance, local faults [slides]
Feb 12
Mon
No class (Family Day); no office hours
Feb 14
Wed
Fault Tolerance, local faults (continued) [slides]
Feb 16
Fri
RAID [slides]
Project 1 due
Feb 19
Mon
No class (UBC reading break); no office hours
Project 1 demos/marking Feb 19-23
Feb 21
Wed
No class (UBC reading break); no office hours
Project 1 demos/marking Feb 19-23
Feb 23
Fri
No class (UBC reading break); no office hours
Project 1 demos/marking Feb 19-23
Feb 26
Mon
Feb 28
Wed
Mar 2
Fri
Project 2 proposal drafts due
Mar 5
Mon
Mar 7
Wed
Mar 9
Fri
Project 2 final proposals due
Mar 12
Mon
Mar 14
Wed
Mar 16
Fri
Mar 19
Mon
Mar 21
Wed
Mar 23
Fri
Project 2 group meetings with designated TA
Mar 26
Mon
Mar 28
Wed
Mar 30
Fri
No class (Good Friday); no office hours
Apr 2
Mon
No class (Easter); no office hours
Apr 4
Wed
Apr 6
Fri
Project 2 code and final reports due
Last day of class
Apr 9-20 Project 2 demos/marking
Apr 16 Final exam at 8:30 AM. Room TBD.

Go resources

Go is a systems language designed at Google. It is especially well suited to building distributed systems. Like with any language, the fastest way to become proficient at Go is to put in the time writing programs in Go. Here are some resources to get you started:

We will be using Go version 1.9.2 (the most recent version).

Assignments

There are two assignments. All assignments must be completed in Go and you must work on them individually.

Solution must be submitted using the stash server by 11:59PM of the day of the deadline. Special instructions for compiling/running the code should be included as a README.txt file.

Assignments will be primarily marked based on functionality. Some partial marks will be given to assignments that partially fulfill the specifications, but this is done at our discretion. It is therefore in your best interest to submit a complete solution. We also encourage you to properly document and gofmt your code.

To access the hand-in git repository for assignment X as student with undergrad userid UID, run the following command:

git clone https://stash.ugrad.cs.ubc.ca:8443/git/CS416_2017W2_/asX_UID.git

Add your solution (and don't forget to push!) to the repository by the deadline.

Assignment deadlines are listed in the schedule above and below. Assignment descriptions will be linked to from this page once they are available.

Project 1

Project 1 is a larger assignment that must be done in a group of 4 students and must be deployed on Azure.

Deliverables

All project 1 deliverables are due at 11:59PM on their respective dates.

  • Implementation. We expect your repository to include a detailed README file that explains the design of your implementation.
  • Project demo: a 20-minute private demo of your project to the instructor/group TA, including a technical Q/A regarding the project design and implementation.
    • The stash project repositories will be frozen after you submit your code. You must use this frozen code to demo your project

Project 2

Project 1 is an open-ended project that must be done in a team of 3-5 people and must be (at least partially) deployed on Azure.

Deliverables

All project 2 deliverables are due at 11:59PM on their respective dates.

  • Project proposal: a paper detailing the problem, your proposed approach/solution, a realistic timeline for your team, and a SWOT analysis for your team.
  • Prototype implementation: must involve substantial development effort. The prototype git repository must be shared with the course staff.
  • Project report: a paper detailing the problem, your approach/solution, design of your prototype, and an evaluation of the prototype.
  • Project demo: a TBD-minute private demo of your project to the instructor/group TA, including a technical Q/A regarding the project design and implementation.

Exam

To practice for the exam we will go over 1-3 questions at the start of each class. You can also download the complete set of practice questions we have covered thus far (updated continuously).

Final exam Monday, Apr 16 at 08:30 (AM). Room TBD.

Grading

Final course mark will be based off of:

  • Assignment 1: 5% (+2% extra credit)
  • Assignment 2: 20%
  • Project 1: 20%
    • Code: 10%
    • Demo: 10%
    • Peer review multiplier
  • Project 2: 35%
    • Proposal: 10%
    • Report and code: 15%
    • Demo: 10%
    • Peer review multiplier
  • Final exam: 20%

Note that the assignments are individual efforts, while the two projects must be team efforts.

Late policy

The deadline for any assignment can be extended by one day with a 20% penalty to the mark. Assignments will not be accepted 24 hours past the original deadline.

Deadline for project 1 can be extended under the same terms as the assignments.

Deadlines for project 2 cannot be extended.

If you have an emergency (e.g., health) that prevents you from meeting a deadline. You must notify the instructor before the deadline.

How to do well in this course

Learn Go early and practice it regularly. Learning a new language while being time constrained is stressful and not fun. Since the assignments rapidly increase in their difficulty, it will be to your advantage to learn Go as quickly as possible and to learn it well. The posted Go resources are a great starting point, but reading is no substitute for practice, bug, debug, practice, practice, bug, coffee, debug, practice, ...

Do not skimp on software engineering. Distributed systems are hard. They are hard to understand, to build, to debug, to run, to trace, to document, etc. Do not make your life any more difficult. Use best practices from software engineering to help you in this course. Write unit and integration tests, use version control, document your code with comments, write small prototypes, refactor your code, make your code readable and easy to run and debug. If you fail to follow best practices, they will come back to bite you later on. Unfortunately, this course will not explicitly teach you these best practices, but you probably took a course that introduced you to these concepts. If you have any questions, just ask us on Piazza.

Choose your teammates, wisely. Some assignments will depend critically on your ability to work effectively with one other student. You are responsible for resolving personal and technical differences among teammates on your own. Let us know as early as possible if you have team concerns, before they turn into crises.

Reach out for success. This is intended to be a challenging fourth year course, but that does not mean that you have to work through it on your own! The course piazza should be your first stop for all technical questions. The course has specific office hours (see top of page), but I and the TAs are flexible. Send any of us an email to schedule a time to discuss the course, the assignments, etc. University students often encounter setbacks from time to time that can impact academic performance. Discuss your situation with us or an academic advisor as early as possible. For help in addressing mental or physical health concerns, including seeing a UBC counselor or doctor, visit this link.

Academic honesty and collaboration guidelines

The department has a detailed policy regarding collaboration and plagiarism. You must familiarize yourself with this policy.

Acknowledgments

Many of the materials used in this course are derived from CMU's 15-440: Distributed Systems course from Spring 2014, and are used with permission from the content authors.