Modern Scheduling for Modern Applications with Nomad

© 2018 HashiCorp
Nomad
Modern Scheduling for
Modern Applications
Jasmine Dahilig

80%+ companies are
deploying containers with
Multiple OSes across
Multiple Clouds
Majority of surveyed organizations are
deploying containers with both Linux and
Windows, across on-premises and multiple
clouds
40% of surveyed organizations cited
“complexity” as the number one challenge in
container deployment.
Management Complexity
is a top challenge in using
and deploying containers
https://www.cncf.io/blog/2018/08/29/cncf-survey-use-of-cloud-
native-technologies-in-production-has-grown-over-200-percent/
https://goto.docker.com/rs/929-FJL-178/images/IDC-
containerplatform-wp.pdf

A Common Cloud Operating Model
App
App
Run
Provision
Connect
Secure
Compliance&Governance

The Need for a Modern
Orchestrator

© 2018 HashiCorp
The Move to
Containers and
Clouds
5
● Adopt containers and
microservices for new applications
● Re-architect & migrate existing
applications
● Segment of legacy applications
remains the same

© 2018 HashiCorp
The Fundamental
Needs for a Container
Orchestrator
6
How do we run
containers in
production?
”

© 2018 HashiCorp
Challenges of Moving
to Containers
7
● Lack of budget or time to refactor
existing applications
● Increased complexity to support
mixed systems and workflows
● Limited time to meet IT/Business
requirements - Incremental vs
Overhaul

© 2018 HashiCorp
Guiding Principle
Orchestrate Any
Application
8
● Bringing modern orchestration benefits to
all - containerized, non-containerized and
batch applications
● A simple, lightweight layer that can be
integrated with any existing infrastructure
● A single, unified workflow to accelerate
incremental application modernization

© 2018 HashiCorp
NOMAD ECOSYSTEM
Single
Orchestrator
for Clouds

Application Deployment as Code
● Declarative specification using
HCL (like Terraform) or JSON
● Set the deployment rules for
applications fast and intuitively.
Define tasks, images, resources,
priorities, constraints, service
registrations, secrets and other
information required to deploy the
application.
job “my_job" {
region = "us"
datacenters = ["us-west-1", "us-east-1"]
type = "service"
group "web" {
count = 5
task "frontend" {
driver = "docker"
config {
image = "hashicorp/web-frontend"
}
resources {
cpu = 500 # MHz
memory = 128 # MB
network {
mbits = 100
port "http" {}
port "https" {
static = 443
TERMINAL

Intuitive Deployment Rules
job “my_job" {
region = "us"
type = "service"
group "web" {
count = 5
task "frontend" {
driver = "docker"
config {
}
resources {
cpu = 500 # MHz
memory = 128 # MB
network {
mbits = 100
port "http" {}
port "https" {
static = 443
job
# define the deployment rules for applications
_ group
# defines a series of tasks that should be co-located on
the same Nomad client
_ task
# defines a command, service, application or
"set of work" to execute, such as a docker
container, webapp or batch processing. Tasks
are executed by their driver

job “my_job" {
region = "us"
datacenters = ["us-west-1", "us-e
type = "service"
group "web" {
count = 5
task "frontend" {
driver = "docker"
config {
image = "hashicorp/web-fron
}
resources {
cpu = 500 # MHz
memory = 128 # MB
network {
mbits = 100
port "http" {}
port "https" {
● Batch Scheduler is optimized for fast placement for short-lived workload.
Example: Daily reports, transactions, billing invoices
● Service Scheduler is optimized for long-running workloads.
Example: Business-critical applications, customer facing webapps,
database
● System Scheduler is optimized for background tasks
Example: Logging/monitoring, security, background processes
Schedulers to Run All Types of Workloads

Enable Flexibility with Extensible Drivers
job “my_job" {
region = "us"
type = "service"
group "web" {
count = 5
task "frontend" {
driver = "docker"
config {
}
resources {
cpu = 500 # MHz
memory = 128 # MB
network {
mbits = 100
port "http" {}
port "https" {
static = 443
● Task Drivers execute tasks on the Nomad Client and provide
resource isolation
● First-class support of a broad set of workloads across all
major operating systems

Robust Application Update Strategy
Automate job update and migration
to minimize down time
● Rolling Updates
● Blue/Green deployments
● Canaries deployments
● Updates can be gated on Consul
health checks and automatically
reverted
job “my_job” {
update {
max_parallel = 3
health_check = "checks"
min_healthy_time = "10s"
healthy_deadline = "10m"
auto_revert = true
canary = 1
stagger = "30s"
}
}
TERMINAL

Nomad Architecture - Single Process
Single Binary
(<35MB)
NOMAD
AGENT
NOMAD
SERVER
NOMAD
CLIENT
Nomad Server forms the control plane for
scheduling.
$ .nomad -config=server.hcl
Nomad Client runs on the node which
registers with the servers, watching for any work to
be assigned and execute tasks
$ .nomad -config=client.hcl

Nomad Architecture - Single Region

Overall Scheduling Process
Define the
“Desired States”
of tasks by users,
bounded by hard
and soft
constraints
Triggered by any
change of Jobs or
Nodes when
Nomad needs to
re-evaluate the the
“state of world”
Nomad generates
a plan on how a
set of tasks in a
job should be run
on a particular
node
Nodes form a
resource pool
where the tasks
can be executed.
Nomad monitors
their health status
Nomad scheduler is responsible for processing an
evaluation and generating an allocation plan.

Improved Application Resiliency

Improved Resource Utilization
● Improve resource utilization by densely
scheduling applications over underutilized
resources

Native Integration with
Vault and Consul

Secrets Management with Vault
● Automatic Vault token retrieval
● Automatic Vault token renewal
● Automatic secret retrieval and
renewal via template stanza
Job file
job “my_job" {
group "example" {
task "server" {
vault {
policies = ["cdn", "frontend"]
change_mode = "signal"
change_signal = "SIGUSR1"
}
}
}
}
TERMINAL
retrieve
renew

Service Discovery with Consul
● Built-in service discovery,
registration, and health check
monitoring for all applications
deployed under Nomad

Service Mesh with Consul
● Network Namespaces to create
isolated network for a task group
● Native Consul Connect integration
to launch sidecar proxies for
applications
● Intentions*are defined in Consul
and transparent to job spec
authors as applications scale up
and down
*Note: Intentions define access control for services via
Consul Connect and are used to control which services
may establish connections.

Monitoring
● The Nomad client and server
agents collect runtime telemetry.
● Operators can use this data to
gain real-time visibility into their
Nomad clusters and improve
performance.
● The metrics can be exported to
tools like Prometheus, Grafana,
Graphite, DataDog, and Circonus.
telemetry {
publish_allocation_metrics = true
publish_node_metrics = true
}
telemetry {
datadog_address = "dogstatsd.company.local:8125"
datadog_tags = ["my_tag_name:my_tag_value"]
}

Specialized Hardware with Device Plugins
Run any workload against any
hardware infrastructure with
extensible device plugins
● Nomad clients discover and
fingerprint the attributes of
available hardware resources in
addition to existing built-in
resources
● plugin also assists the Nomad
client in making the allocated
device available to run the task
type DevicePlugin interface {
Fingerprint(ctx context.Context) (<-chan *FingerprintResponse, error)
Reserve(deviceIDs []string) (*ContainerReservation, error)
Stats(ctx context.Context, interval time.Duration) (<-chan
*StatsResponse, error)
}
TERMINAL

What’s New with Nomad 0.11
Enhance Core Orchestration Capabilities

Container
Storage
Interface
Deploy stateful
applications with any
storage provider of choice
(EBS, EFS, etc.)
Task
Dependencies
Run interdependent
applications in their
sequential orders easily
and efficiently at scale
Autoscaling
Dynamically scale
application instances
based on real-time load
without manual
intervention
Nomad 0.11 Key Features | OSS
Remote Exec
(UI)
Directly execute
commands in running
allocations through the
Nomad UI for faster
operability

Audit Logging
Provides administrators with a
complete set of records for all user-
issued actions to fulfill compliance
requirements.
[Governance & Policies Module]
Nomad 0.11 Key Features | ENT

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Modern Scheduling for Modern Applications with Nomad

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