Deployment and Provisioning Flashcards
Common reasons why EC2 instnaces may fail to launch
- InstanceLimitExceeded error
- you have reached the limit on teh number of instnaces you can launch in a region
- aws sets default limits on the number of instances you can run on a per-region basis - 20 by default
t
InsufficientInstanceCapacity error
-AWS does not currently have enough available On-Demand capacity to service your request
y
____ allows you to create storage volumes and attach them to your EC2 instances.
EBS
___ can be used to craete.a file system, run a database, run an operation system, etc.
EBS
____ backend storage - used fr OS and databases which can be IO intensive.
SSD
2 different variants of SSD:
gp2 ___ - boot volumes
io1 ___ - IO intensive, NoSQL/relational databases, latency sensitive workloads
____ used to benchmark performance for SSD volumes
general purpose
Provisioned IOPS
IOPS
IOPS capability is dependent on the size of your volume:
gp2 volumes: (minimum 100 IOPS) 3 IOPS/GB up to a max of _____ IOPS
io1 volumes: 50 IOPS/GB to a amx of _____ IOPS
16,000
64,000
what happens if you are using gp2 and your workload exceeds the IOPS limit of teh gp2 volume you have provisioned?
you will start to get your IO requests queing
depending on your apps seneitivity to IOPS and latency, you may see your app becoming slow.
Hitting the IOPS limit of our gp2 Volume
what can you do about it?
explain the 2 approaches to address hitting the IOPS limit:
- For gp2, you can increase the size of your volume - but if your volume is already 5.2T or moer, you will have already reached teh 16,000 IOPS limit for gp2 volumes
- If you need more tahn 16,000 IOPS, you will need to change your storage class to Provisioned IOPS
A bastion host is located in your ____ subnet
public
a bastion host allows you to connect your ec2 instances using ___ or ___ protocols
ssh or rdp
T or F
you can log in to the Bastion host over the internet, from your desktop
T
If the settings allow it
T or F
the bastion host is used to initiate an SSH/RDP session over the private subnet to your ec2 instances in teh private subnet
T
____ load balancers scale automatically to adapt to your workload
application
xx messages indicate that something has gone wrong on the client side
400
xx messages relate to server side errors
500
= Bad/malformed request - ie: the header is malformed
400
Unauthorized - user access denied
401
- forbidden - request bloked by WAF access control list
403
- client closed connection before the load balancer could repond, client timeout period may be too short
406
- load balancer received an X-Forwarded-For request headerwith >30 IP addresses - similar to a malformed request
463
- Internal srver error iee: error on the load balander
500
- bad gateway - ie: an app server closed the connection or sent back a malformed response
502
- server unavailble - no registered targets
503
- gateway timeout - ie: ap is not responding - problem with your web server, app server or database
504
- Unauthorized - received an error code from the ID provider when trying to authenticate a user
561
____ load balancers publish metrics to CW for the load balancer and for the backend instances
elastic
t or F
ELB CW metrics help to verify taht your system is performing as expected
T
ELB CW metrics - overall health
_____ number of unsuccessfl conenctions to backend instances
_____ number of healthy insatnces registered
___ number of unhealthy instances
____2xx,3xx,4xx,5xx
BackendConnectionErrors
HealthyHostCount
UnHealthyHostCount
HTTPCode_Backend
____ number of seconds taken for ergistered instance to respond/connect
Latency
____ number of requests completed/connections made during teh specified interval (1 or 5 min)
RequestCount
____ number of pending requests, max queue size is 2014, additional requests will be rejected (Classic only)
SurgeQueueLength
_____ number of requests being rejected because the surge queue is full (Classic only)
SpilloverCount
____ is a mangment tool which gives you visibility and control over your AWS infrastracture.
It integrateswith CW allowing you to view your dashboards, view operational data and detect problems.
Includes ___ which automates operational tasks across resources - ie: security patching, package installs.
Organize your inventory, grouping resources together by applicaiton or environment - including on prem systems.
Systems Manager (SSM)
Run Command
_______
allows you to run pre-defined commands on one or more EC2 instances.
- stop, restart, terminate, re-size instance
- attach/detach EBS volumes
- create snapshots, abckup dynamoDB tables
- apply patches and upadtes
- run an ansible playbook
- run a shell script
run command
3 types of placement groups:
___ instances are all created in a single AZ
___ instances are created in logical segments called partitions, each located in a separate rack(s), with independent network and power.
____ each instance is created in a separate rack, with independent network and power.
CLuster, Partition, Spread
___ placement groups
- all instances created in same AZ
- all nodes within the placement group can talk to all other nodes within the placement group at the full line rate of 10Gbps
- Not great availability (ideally, you’d want a copy of your stack in another AZ as well)
- great if the separate compnents in your app require high network throughput
cluster
_____ placement group
- instances are created in logical segments called partitions, can be multi-AZ
- each partition is in a separate rack(s), with independent network and power
- partitions cannot share racks which helps reduce the impact of a failure
- great for large distribuetd/replicated workloads, such as HDFS< HBase, and Cassandra
Partition
___ placement groups
- instances placed on distinc racks, each with its own network and power source
- recommend for apps with small number of critical intances taht should be separated
- reduces teh risk of simultaneous failures when instances share the same racks.
- gurantees your instances are places in different racks with isolated power and networking.
spread
