74 lines
No EOL
2 KiB
Markdown
74 lines
No EOL
2 KiB
Markdown
18 Setembro 2023 - #ASCN
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## Why distributed systems?
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- Modularity, decoupling different concerns.
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- Performance.
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- Dependability
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## How to distribute?
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### 1. Monolythic system
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- Architecture: [[Monolithic system.excalidraw]]
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- Multiple services for multiple targets in the same server
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## 2. Distributed systems
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- Main distribution concerns:
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1. Replication
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2. Partitioning
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3. Service-orientation
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- All of these address scaling out a service/application.
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- Not mutually exclusive, can be combined.
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### 2.1 Replication
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- Architecture: [[Replication.excalidraw]]
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- Multiple copies of the same data and functionality
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- Addresses resilience and scale-out
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### 2.2 Partitioning
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- Architecture: [[Partitioning.excalidraw]]
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- A server is split horizontally (Sharding).
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- Addresses scale-out.
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- Can be applied to computation, data, ...
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### 2.3 SOA - Service-Oriented Architecture
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- Architecture: [[SOA.excalidraw]]
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- Addresses scale-out and modularity.
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- Example: micro-services.
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#### 2.3.1 Microservices
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- Each service implements specific functionality.
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- Services can scale independently.
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- Decomposition may be troublesome: how micro is micro?
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- Consistency.
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- Complex deployment and testing
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## Distributed architectures
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### 1. Client-server
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- Architecture: [[client-server.excalidraw]]
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- Functionality and data are in the server.
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- A stub runs embedded in the client.
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- The stub is part of the server software package
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- E.g., the Web (“protocol” is HTTP)
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### 2. Proxy Server
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- Architecture: [[proxy.excalidraw]]
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- Multiple servers can be used transparently.
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- The proxy is a performance and availability bottleneck.
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- E.g. MongoDB
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### 3. Master Server
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- Architecture: [[master.excalidraw]]
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- Scale out!
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- E.g. HDFS
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### 4. Server Group
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- Architecture: [[server-group.excalidraw 1]]
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- All servers can process requests.
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- Coordination may be necessary.
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- Resiliency!
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- E.g. ZooKeeper
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### 5. Bus
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- Architecture: [[server-group.excalidraw 1]]
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- All servers can process requests.
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- Coordination may be necessary.
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- Resiliency!
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- E.g. ZooKeeper |