The document discusses auto-scaling in multi-tier container topologies, highlighting common issues such as application design, unpredictable spikes, and slow provisioning. It emphasizes the use of Docker containers for efficient scaling and the necessity of load balancers when scaling applications horizontally. Additionally, it outlines scaling considerations for various layers including web, database, and storage, along with details on configuration and triggers for scaling actions.

1. Auto Scaling for Multi-Tier
Containers Topology

2. The Problem

3. Not
Expected
Load

4. Your app
becomes
slow

5. Your app
is down

6. Solution
Scale your
application

7. Issues that prevent us to do scaling
• Application is not designed for scaling
• We cannot predict our spikes
• The provisioning of each new instance takes much time
• We never know what bottlenecks to expect

8. Let’s try to eliminate
these issues

9. Design your application
for multiple instances support

10. Containers
can help
you
provision
apps
faster!

11. Application Container
Use Docker for packing applications into
containers

12. MultiplicityofGoodsMultiplicityofmethodsfor
transporting/storing
DoIworryabouthow
goodsinteract?
CanItransportquickly
andsmoothly?
…in between, can be loaded and
unloaded, stacked, transported
efficiently over long distances,
and transferred from one mode
of transport to another
A standard container that is
loaded with virtually any
goods, and stays sealed
until it reaches final delivery.
Shipping container for goods

13. Static website Web frontendUser DB Queue Analytics DB
Development
VM
QA server Public Cloud Contributor’s
laptop
MultiplicityofStacks
Production
Cluster
Customer Data
Center
…that can be manipulated
using standard operations
and run consistently on
virtually any hardware
platform
An engine that enables any
payload to be encapsulated
as a lightweight, portable,
self-sufficient container…
Docker is a shipping container system for code
Multiplicityofhardware
environments
Doservicesandapps
interactappropriately?
CanImigratesmoothly
andquickly?

14. Why Docker containers are better for scaling
than VMs?

15. Designed
for
High
Availability

16. Lets Scale
Using Docker

17. Simple WordPress application

18. The Goal

19. • You must use load balancer once
you scale an app horizontally
• Keep look at sticky load balancing
• Load balancer can be scaled
horizontally
• Dynamic scaling in and out is also
possible!
Load balancing consideration

20. Scaling of the web layer
• Should be done just in time
• Load balancer should be aware
of resizing at the web layer
• Requires additional actions for
stateful applications:
• Use of storage replication
• Use of shared persistent
storage

21. Database scaling consideration
• Relational databases usually
scale good only vertically
• Relational database usually can’t
be scaled horizontally in a
runtime
• We have to prepare a database
cluster of a fixed size

22. The topology that we try to create

23. {
"extip": true,
"cloudlets": 8,
"count": 2,
"nodeType": "docker",
"nodeGroup": "bl",
"docker": {
"image": "jelastic/wp-nginxlb"
},
"displayName": "Load balancer"
}
Load balancer layer declaration

24. {
"cloudlets": 8,
"count": 2,
"nodeType": "docker",
"nodeGroup": "cp",
"docker": {
"image": "jelastic/wp-nginxphp",
"links": "sqldb:db",
"volumes": ["/var/www/webroot/ROOT"],
"volumeMounts": {
"/var/www/webroot/ROOT": {
"readOnly": false,
"sourcePath": "/data",
"sourceNodeGroup": "storage"
}
}
},
"displayName": "AppServer"
}
Web layer declaration

25. {
"cloudlets": 8,
"nodeGroup": "storage",
"nodeType": "docker",
"docker": {
"image": "jelastic/storage"
},
"displayName": "Storage"
}, {
"cloudlets": 8,
"count": 2,
"nodeType": "docker",
"nodeGroup": "sqldb",
"docker": {
"image": "jelastic/wp-db"
},
"displayName": "Database"
}
DB & Storage layer declaration

26. Set your triggers for each layer

27. "onAfterScaleIn[nodeGroup:cp]": {
"call": "ScaleNodes"
},
"onAfterScaleOut[nodeGroup:cp]": {
"call": "ScaleNodes"
},
"onInit": {
"call": [ "configureDBReplication","setupWP",
"ScaleNodes", "enableAutoScaling" ]
}
}
Scaling Triggers declaration

28. {
"id": "ScaleNodes",
"onCall": [{
"execCmd": [{
"commands": ["echo "" > /etc/nginx/upstreams/common"],
"nodeGroup": "bl"
}]
}, {
"forEach(node:nodes.cp)": {
"execCmd": {
"commands": ["echo "${@node.intIP}" >>
/etc/nginx/upstreams/common"],
"nodeGroup": "bl"
}
}
}, {
"execCmd": {
"commands": ["jem balancer rebuildCommon", "/etc/init.d/nginx reload"],
"nodeGroup": "bl"
}
}
]
}
Scaling Triggers Body

29. Use stress tools to simulate load

30. Analyze metrics in each individual microservice

31. THANKS
Register for free
jelastic.cloud
info@jelastic.com