Firstly, pgadmin is a web app.
http://127.0.0.1:60832/browser/
Category Archives: Tech
Terraform Interpolation Syntax
Conditionals
Interpolations can contain conditionals. E.g.
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<span class="n">resource</span> <span class="s2">"aws_instance"</span> <span class="s2">"web"</span> <span class="p">{</span> <span class="n">subnet</span> <span class="o">=</span> <span class="s2">"${var.env == "</span><span class="n">production</span><span class="s2">" ? var.prod_subnet : var.dev_subnet}"</span> <span class="p">}</span> |
using ternary operation:
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CONDITION ? TRUEVAL : FALSEVAL |
i.e. if var.env == "production"
then subnet = var.prod_subnet
else subnet = var.dev_subnet
https://www.terraform.io/docs/configuration/interpolation.html#conditionals
Scaling website with AWS
Billing: reducing costs on AWS, Kubernetes, etc
Our monthly AWS bill is millions of dollars per year. So, we’re always trying to reduce costs.
Here are a few tips – some of these are Kubernetes but mainly AWS:
- reduce size of pods
- get the right node size and type
- get the right instance class
- don’t over-provision storage
- clean up lost resources
Cost Optimization is also one of the five pillars of the Well-Architected Framework from AWS: https://aws.amazon.com/architecture/well-architected/
i.e. https://d1.awsstatic.com/whitepapers/architecture/AWS-Cost-Optimization-Pillar.pdf
Billing Dashboard AWS: https://console.aws.amazon.com/billing/home
Qliq
Business Intelligence software:
Finder dialog – show dot files
Wizards: why they suck
You see it everywhere – from Windows dialogs to AWS.
Wizards are supposed to simplify a task by focusing on just a few specific items.
But the problem is that you can end up losing track of the big picture whilst you’re traversing a long wizard.
Spotify: reorder playlists
You can only do this on the Desktop app – not web or mobile.
Hold and drag.
West Midlands Space Centre
Aim: launch at least 1 satellite from the West Midlands
How: using Rockoon technology
Phases:
- launch high altitude balloon
- launch rocket
- launch rockoon
- launch rockoon with satellite
- launch rockoon with satellite to LEO
- launch rockoon with satellite to the Moon
Phase 1
Pico tracker: http://www.loratracker.uk/?p=30
Useful links:
UKHAS:
- https://ukhas.org.uk/
- https://groups.google.com/forum/#!forum/ukhas
- IRC: #highaltitude on Freenode
BIS West Midlands:
Black Knights Rocket club:
Kubernetes: EKS – Warning FailedScheduling – default-scheduler no nodes available to schedule pods
I spun up an EKS cluster and, when I ran:
kubectl get pods -n kube-system
got
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NAME READY STATUS RESTARTS AGE kube-dns-fcd468cb-8fhg2 0/3 Pending 0 1h |
More detail needed:
kubectl describe pods -n kube-system
Warning FailedScheduling 2m13s (x345 over 102m) default-scheduler no nodes available to schedule pods
Looking in EC2 Instances, I could see 2 EKS nodes running with the correct AMI IDs.
But Kubernetes can’t see these nodes. E.g.
kubectl get nodes
No resources found.
Note: low level objects like nodes aren’t namespaced – https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/#not-all-objects-are-in-a-namespace