This talk is about distributed systems testing of Galera with NetEm and Docker!
Video of the talk: https://www.youtube.com/watch?v=YBuuvhSO38s&list=PLctlsn9Gs8wbx47tuhxuNytdrsDf_LWI2&index=1
Playlist: https://www.youtube.com/playlist?list=PLctlsn9Gs8wbx47tuhxuNytdrsDf_LWI2
4. Introduction
Seed quotes..
“ ’Network is reliable’ - a fallacy of the 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. ” - Leslie Lamport
“ Never attribute to malice that which is adequately
explained by stupidity. ” - Hanlon’s Razor
“ Never attribute to Byzantine failure which can be
explained by an ill node(s) ” - Me
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 4 / 41
5. Introduction
Seed quotes..
“ ’Network is reliable’ - a fallacy of the 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. ” - Leslie Lamport
“ Never attribute to malice that which is adequately
explained by stupidity. ” - Hanlon’s Razor
“ Never attribute to Byzantine failure which can be
explained by an ill node(s) ” - Me
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 4 / 41
6. Introduction
Seed quotes..
“ ’Network is reliable’ - a fallacy of the 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. ” - Leslie Lamport
“ Never attribute to malice that which is adequately
explained by stupidity. ” - Hanlon’s Razor
“ Never attribute to Byzantine failure which can be
explained by an ill node(s) ” - Me
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 4 / 41
7. Introduction
Seed quotes..
“ ’Network is reliable’ - a fallacy of the 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. ” - Leslie Lamport
“ Never attribute to malice that which is adequately
explained by stupidity. ” - Hanlon’s Razor
“ Never attribute to Byzantine failure which can be
explained by an ill node(s) ” - Me
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 4 / 41
16. Details
But why
▶ The ‘P’ in CAP
▶ WAN scalability
▶ Real Reason - fun!
▶ Tolerance to latency variance
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 10 / 41
17. Details
But why
▶ The ‘P’ in CAP
▶ WAN scalability
▶ Real Reason - fun!
▶ Tolerance to latency variance
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 10 / 41
18. Details
But why
▶ The ‘P’ in CAP
▶ WAN scalability
▶ Real Reason - fun!
▶ Tolerance to latency variance
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 10 / 41
19. Details
But why
▶ The ‘P’ in CAP
▶ WAN scalability
▶ Real Reason - fun!
▶ Tolerance to latency variance
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 10 / 41
20. Details
But why
▶ Failures in warehouses.
▶ Not quorum, but consensus.
▶ Real world networks and synchronous replication
- Delay
- Partition
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 11 / 41
32. Details
Docker
▶ Why not virtualize
♦ Occam
♦ Namespaces
▶ Simplicity
♦ Network
♦ One application per node
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 23 / 41
33. Details
Docker
▶ Portability
- See same qualitative behavior that I do.
▶ Reproducibility
- Makes it determinstic
▶ Configurable and CI
- Byproducts
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 24 / 41
40. Details
Eviction
▶ Aim
▶ Quorum required
- Why? - Not shoot each other
- Non-PC nodes also.
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 31 / 41
41. Details
Eviction
▶ Aim
▶ Quorum required
- Why? - Not shoot each other
- Non-PC nodes also.
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 31 / 41
42. Details
Coredumps with Docker
▶ Breakdown of abstraction
▶ Lack of isolation
▶ What was done
- Volumes
- core_pattern & sysctl
- suid and ulimit
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 32 / 41
43. Details
WAN Segments
▶ How they work
▶ Random allocation
▶ Joiner starvation
▶ Simulates data center
▶ Donor selection
Raghavendra Prabhu (Percona) Dock’em 13 January, 2015 33 / 41