PingCAP-Infra-Meetup-105-Chaos practicein TiDB
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本次杜川老师的分享主要分成三个部分：
1.首先通过对现有 Streaming 系统和 Batch 系统的分析，讨论了在数据处理领域 Streaming 和 Batch 的异同，明确了 Streaming 的核心本质，探讨了 Streaming 和 Batch 融合处理的可能性和必要性，并对现有类似系统进行了简单的分析。
2.简单回顾了 RDMS 中经典的 Volcano 模型的执行流程，探讨了在 RDMS 上支持 Streaming 处理的难点以及 Streaming SQL 设计的关键要素。
3.介绍了 TBSSQL 的设计思路，架构设计和若干关键技术点的方案选择，展示了 TBSSQL 的运行 Demo。并以 TBSSQL 为例，简单介绍了在 TiDB 上增加一个 Feature 的大致思路和入手点。
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1.Chaos practice in TiDB
PingCAP
舒科
2019 年 6 月 1 日
2.Testings in TiDB
● Unit Testing
● Integration Testing
● Performance Testing
● Schroinger Testing
○ Chaos Testing
3.content
● Why Chaos
● Practice in TiDB
● Schrodinger
4.Why Chaos
● Use fault injection
● by Netflix 2010
○ Break things
● Why 2010
○ Netflix move to AWS
○ lots of errors
■ hardware
■ network latency
■ ...
5.Why Chaos (cont.)
● Goal:
○ Make system stronger
● Steps
6.Why Chaos (cont.)
● Samples
○ Chaos in EMC
■ Robot to remove harddisk in BMW POC
○ Chaos in Facebook
■ shutdown a data center
● lack of Chaos
○ 737 - max
7.Why Chaos (cont.)
● Micro service
○ Too complex to understand
● Error always happens
● Do Chaos to Gain
confidence
9.Why Chaos (cont.)
● ETCD bug
● RocksDB bug
● Leader partitioned
● Transfer leader if busy
● Too many regions
● Crashed when processing batch raft
● ...
10.● Why Chaos
● Practice in TiDB
● Schrodinger
11.Chaos practise in TiDB
12.Chaos practise in TiDB (cont.)
● Region hearbeats
○ check what happened when huge number regions on a machine
○ choose metric: CPU
○ Hypothesize:
■ CPU is still low
○ Experiments
■ 40k regions on a machine
○ What happened?
■ OOM
■ 30% CPU occupied
13.Chaos practise in TiDB (cont.)
● Choose Metrics
○ often QPS
○ CPU
○ memory
● Hypothesis
○ QPS revert to previous level in X seconds
○ QPS drop 1/x
14.Chaos practise in TiDB (cont.)
Error injection
15.Chaos practise in TiDB (cont.)
● Applications
○ kill, kill -9
○ renice
○ sigstop, sigcont
16.Chaos practise in TiDB (cont.)
● Memory
○ cgroup
● Storage
○ fuse
○ rm -rf
● Network
○ tc
○ iptable
17.Chaos practise in TiDB (cont.)
● other errors
○ ETCD key deleted
○ NTP errors
○ ...
18.Chaos practise in TiDB (cont.)
● Observe results
○ Learn from history
19.Chaos practise in TiDB (cont.)
● Observe results
○ Learn from log
20.Chaos practise in TiDB (cont.)
● Automation
○ Take some machines from SRE
○ Deploy
○ Experiment
○ Debug
○ Return
21.● Why Chaos
● Practice in TiDB
● Schrodinger
26.Schrodinger (cont.)
cat
28.Schrodinger (cont.)
Chaos Operator
29.Schrodinger (cont.)
Run with your own Helm charts
