Key DuploCloud concepts
Key concepts for using DuploCloud with Docker and Azure
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Key concepts for using DuploCloud with Docker and Azure
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While deploying Dockerized applications, familiarize yourself with some key concepts and terminologies.
See for a description of DuploCloud Infrastructures and Tenants.
These are virtual machines. In AKS deployments, they are also called Worker nodes. By default, apps within a Tenant are pinned to VMs in the same Tenant.
Service is a DuploCloud term. DuploCloud Services are not Kubernetes Services. Services are microservices that are defined by a Name, DockerImage, and number of replicas in addition to many other optional parameters. Behind the scenes, a DuploCloud Service maps 1:1 either to a Kubernetes deployment set or to a StatefulSet depending on whether the microservice has stateful volumes or not. There are many optional configurations associated with a DuploCloud Service that represent various ways Docker containers can be run. A few of these are:
Environment variables
Host Network Mode
Volume mounts
Entrypoint or command overrides
Resource caps
Health Checks
Allocation tags allow you to control which Hosts a Service can run on by specifying tags on both the Host and the Service. Services without allocation tags can be scheduled on any Host.
Docker Services use case-insensitive, substring-based matching.
For example, if a Host has the tag HighCpu;HighMem, a Service tagged highcpu or cpu would match and be eligible to run on that Host.
Kubernetes Deployments use exact, case-sensitive matching based on Kubernetes node labels and node selectors. For example, a Host tagged frontend-prod will only match a Service with the exact same tag: Frontend-Prod or frontend-prod-1 will not match. Kubernetes allocation tags must start and end with an alphanumeric character and may only contain letters, numbers, hyphens (-), or periods (.)
If a Host is tagged and a matching Service exists, the Host may still be used by untagged Services unless all Services in the tenant are tagged. To fully isolate Hosts for a specific purpose, ensure all Services use allocation tags.
By default, Docker containers have their own network addresses. you may want these containers to use the same network interface as the VM. This is called Host Network Mode.
If a service must be accessed by other services, it needs to be exposed using a Load Balancer. Supported Load Balancers include:
A Network Load Balancer (NLB). An NLB distributes traffic across several servers by using the TCP/IP networking protocol. By combining two or more computers that are running applications into a single virtual cluster, NLB provides reliability and performance for web servers and other mission-critical servers.
An Application Load Balancer (ALB). An ALB provides outbound connections to cluster nodes inside the AKS virtual network, translating the private IP address to a public IP address as part of its Outbound Pool.