Building a Cloud Native Bank

A brief look at how Monzo, a UK based digital bank, have leveraged the features of Amazon's public cloud to build a secure, cloud native, banking platform — using modern open source technologies and common software development practices.

Presented at the AWS User Group UK meetup

Transcript

1. Building a Cloud-Native Bank Matt Heath, Monzo
2. ! ⛅ #
3. Hi, I’m Matt
4. @mattheath
7. Nov 2015 Oct 2018 CUSTOMER
 GROWTH
8. $ 1,031,133
9. £4 billion spent %
18. #
19. &
21. '
22. LICENCE WITH RESTRICTIONS WE ARE HERE A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! FEB 2015 JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY JUN JUL MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC PRE APPLICATION APPLICATION MOBILISATION LAUNCH LICENCE WITH RESTRICTIONS 50K MAX DEPOSIT WE ARE HERE A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY JUN JUL MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC E APPLICATION APPLICATION MOBILISATION LAUNCH LICENCE WITH RESTRICTIONS WE ARE HERE AUG
 2017 JAN
 2016 Feb
 2015 APR
 2017 A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! FEB 2015 JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC PRE APPLICATION APPLICATION MOBILISATION LICENCE WITH RESTRICTIONS WE ARE HERE
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44. EXTENSIBLE SCALABLE RELIABLE SECURE
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46. Application
47. Application
48. APPLICATION Application
52. LICENCE WITH RESTRICTIONS WE ARE HERE A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! FEB 2015 JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY JUN JUL MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC PRE APPLICATION APPLICATION MOBILISATION LAUNCH LICENCE WITH RESTRICTIONS 50K MAX DEPOSIT WE ARE HERE A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY JUN JUL MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC E APPLICATION APPLICATION MOBILISATION LAUNCH LICENCE WITH RESTRICTIONS WE ARE HERE AUG
 2017 JAN
 2016 Feb
 2015 APR
 2017 A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! FEB 2015 JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC PRE APPLICATION APPLICATION MOBILISATION LICENCE WITH RESTRICTIONS WE ARE HERE
53. A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! FEB 2015 JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY JUN JUL MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC PRE APPLICATION APPLICATION MOBILISATION LAUNCH LICENCE WITH RESTRICTIONS 50K MAX DEPOSIT WE ARE HERE A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY JUN JUL MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC E APPLICATION APPLICATION MOBILISATION LAUNCH LICENCE WITH RESTRICTIONS WE ARE HERE AUG
 2017 JAN
 2016 Feb
 2015 APR
 2017 PREPAID
 CARD
 LAUNCH LICENCE WITH RESTRICTIONS WE ARE HERE A UK banking licence is authorised by the PRA and regulated by the PRA and FCA1, allowing deposit- taking and balance sheet lending. Once granted, it allows firms to passport across Europe, accessing This is followed by a “mobilisation” phase during which final capital is raised and IT systems are completed, before launching to the public. We received a UK banking licence in August 2016! FEB 2015 JAN 2016 JAN 2017 MAR FEB FEB APR MAR MAR APR MAY APR JUN MAY JUL JUN AUG JUL SEP AUG NOV SEP DEC NOV DEC PRE APPLICATION APPLICATION MOBILISATION LICENCE WITH RESTRICTIONS WE ARE HERE
58. ?
59. EC2
 Instance
60. instance instance
61. instance instance instance instance instance instance
62. instance instance instance instance instance instance { { { eu-west-1a eu-west-1b eu-west-1c
63. instance instance instance instance instance instance Kubernetes
64. instance instance instance instance instance kubelet
65. kubelet kubelet kubelet kubelet kubelet kubelet
66. kubelet kubelet kubelet kubelet kubelet kubelet Kubernetes Master
67. kubelet kubelet kubelet kubelet kubelet kubelet Kubernetes Master etcd
68. kubelet kubelet kubelet kubelet kubelet kubelet Kubernetes Master etcd
69. etcd
70. etcd etcd etcd
71. etcd etcd etcd etcd etcd etcd etcd etcd etcd
72. etcd etcd etcd etcd etcd etcd etcd etcd etcd quorum = 5 or more nodes alive (n/2+1)
73. etcd etcd etcd etcd etcd etcd etcd etcd etcd quorum maintained
74. etcd etcd etcd etcd etcd etcd etcd etcd etcd quorum maintained '
75. etcd etcd etcd etcd etcd unhealthy machines terminated 0
76. etcd etcd etcd etcd etcd etcd etcd etcd etcd new machines automatically reattach EBS, cluster recovers 1
77. etcd ASG 4 etcd ASG 7 etcd ASG 1 etcd ASG 5 etcd ASG 8 etcd ASG 2 etcd ASG 3 etcd ASG 6 etcd ASG 0 each etcd node is an autoscaling group of 1, with a fixed identity
78. etcd etcd etcd etcd etcd etcd etcd etcd etcd quorum lost 2
79. etcd etcd etcd etcd unhealthy machines terminated 0
80. etcd etcd etcd etcd etcd ASG 7 etcd ASG 1 etcd ASG 8 etcd ASG 2 etcd ASG 6 autoscaling groups start new instances
81. etcd etcd etcd etcd etcd etcd etcd etcd etcd unhealthy machines replaced automatically, EBS reattached, cluster recovers 3
82. Blog
83. kubernetes
84. kubernetes pod pod pod pod pod pod pod pod pod pod
85. pod container service
86. pod scratch container go service
87. kubernetes service service service service service service service service service service
88. kubernetes service service service service service service service service service service
89. kubernetes service service service service service service service service service service
90. kubernetes service service service service service service service service service service
91. kubernetes service service service service service service service service service service service service service
92. kubernetes service service service service service service service service service service
93. kubernetes service Prometheus service service Kafka linkerd Kafka service service Elasticsearch calico API service
96. Request Limit
97. CPU Throttling
99. API
100. API
101. API Gateway API Service API Service API Service API Service API Service API Service API Service API Service
105. API Gateway Accounts Cards Pots Feed Payments …
106. API Gateway Accounts Cards Pots Feed Payments … New
 Exciting
 API!! 5
107. Cards Pots Payments … API Gateway Accounts New
 Exciting
 API!! 0 0 0 0 0 Feed
108. Cards Pots Payments … API Gateway Accounts New
 Exciting
 API!! 0 0 0 0 0 6 Feed
109. API Gateway Accounts Cards Pots Payments … New
 Exciting
 API!! 5 6 Feed
110. Service Service
111. Service Service Service Service
112. Service Service Service Service Kubernetes
 Service
113. Service Discovery Load Balancing Timeouts and Expirations Retries Rate Limiting Connection Pooling Circuit Breaking Failure Detection Metrics and Tracing Interrupts Context Propagation
114. Service Discovery Load Balancing Timeouts and Expirations Retries Rate Limiting Connection Pooling Circuit Breaking Failure Detection Metrics and Tracing Interrupts Context Propagation
115. Service Service Service Service ?
116. Service Service Service Service linkerd
117. Service linkerd
118. Service linkerd service
 discovery
119. Service Service Service Service linkerd service
 discovery
120. Service Service Service Service linkerd
121. Service Service Service Service linkerd
122. Service Service Service Service linkerd
123. Service Service Service Service linkerd
124. kind: DaemonSet metadata: name: linkerd spec: template: spec: containers: - name: linkerd image: ecr:linkerd_vXXX - "/etc/linkerd/linkerd.yaml" volumeMounts: - name: linkerd-config mountPath: /etc/linkerd readOnly: true ports: - name: http containerPort: 443 hostPort: 4140 env: - name: POD_IP valueFrom: fieldRef: fieldPath: status.podIP resources: limits: cpu: 4 memory: 2Gi monzo.com/cpu-period: 2500 requests: cpu: 1 memory: 1Gi services send requests to local
 linkerd daemonset linkerd daemonset pods & services
 on other machines
128. Event Driven
 Architecture
129. Service A Service B Load Balancer Edge Gateway API Service
130. API Service Service A Service B Load Balancer Edge Gateway
131. API Service Service A Service B Load Balancer Edge Gateway Service D Service E
132. API Service Service A Service B Load Balancer Edge Gateway Service C Service D Service E
133. API Service Service A Service B Load Balancer Edge Gateway Service C Service D Service E 6
134. API Service Service A Service B Load Balancer Edge Gateway Service C Service D Service E 6 7
135. API Service Service A Service B Load Balancer Edge Gateway Service C Service D Service E 6 7 7 7 7
136. API Service Service A Service B Load Balancer Edge Gateway Service C Service D Service E 6 7 7 7 7 Service D
137. API Service Service A Service B Load Balancer Edge Gateway Service C Service D Service E 6 Service D
139. API Service API Service Load Balancer Monzo API Gateway API Service
140. API Service API Service Load Balancer Monzo API Gateway API Service
141. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service
142. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF
143. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF AWS API
144. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF AWS API
145. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF AWS API
146. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF AWS API Reject traffic at ALB Update rules
 via API
147. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF AWS API Reject traffic at ALB Update rules
 via API
148. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service AWS Shield AWS WAF 8
149. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service 8
150. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service 8 service
151. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service 8 service &
154. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service 8 service VPC Segregation
 Network ACLs Sec Groups
155. API Service API Service Application Load Balancer (ALB) Monzo API Gateway API Service 8 service 8
156. instance instance instance instance instance instance instance instance instance 9
157. instance instance instance instance instance instance instance instance instance 9 IAM Auditing CloudTrail 8
159. :
161. Ship it and iterate
 Make changes small
 Make changes often Technical debt as a tool
162. API Gateway Accounts Cards Pots Feed Payments … New
 Exciting
 API!! 5
164. Production load tests & Shadow Traffic
165. EXTENSIBLE SCALABLE RELIABLE SECURE
 CHEAP
166. Empower teams
167. monzo.com/careers