VSTS + Octopus Deploy? Why do I see a lot of CI/CD setups with both?

Let me preface why I like to both build and deploy with VSTS:

• Same permissioning end to end
• Line of sight from end to end build and deployment

Reasons I favor Octopus Deploy over VSTS Release:

• Ability to upload packages/artifacts
  • External ones that are maybe one off packages to get deployed for a specific release
• Target Definition
  • When you create Targets or servers you are deploying to, you are able to add a target to one or multiple environments and assign tags/roles to a target. What does this mean? More flexible server definition rather than defining strict Agents to a pool or servers to a Deployment Group, you can allow a target to span multiple (ie: a testing server that spans your Dev and Test environments and only gets triggered on steps that are defined for that role). I realize you can accomplish similar things to this in VSTS but in my opinion it's far more cumbersome.
• Variable Definition
  • Variables can be grouped at a global level and grouped by a specific pipeline/process (that part is similar to VSTS). Variables can also be grouped or scoped by environments or roles (above) so you are able to have different variable values per role per environment; both super granular and flexible. Places this comes in handy is if you have a backend server with a connection string and maybe 2 content delivery nodes (role - content delivery) that get slightly different values than the backend server. At the moment, I do not know (other than creating new environments) how one would accomplish the same in VSTS.
• Process Definition
  • All of the above comes together in the process definition of Octopus Deploy. The super flexible and granular variables and target definition allows you to focus on the actual deployment process rather than getting hung up on the nuances of the UI and its limitations. One example would be defining a process where the first step would be taking something out of a load balancer from a central server, step two deploy code to delivery server one, step three put back in lb, step 4 take out node two from lb called from a central server, step 5 deploy code to node two, and last step, back into load balancer. I realize it's a very simple hypothetical, but within Octopus Deploy, it's one steady process filtered to execute on specific roles, within VSTS you would have to break that down into different agent phases and probably pipelines.

Above are really the biggest points I see to use Octopus Deploy over VSTS Release. Now why would someone use VSTS to build and OD to release/deploy? There are a lot of different factors that go into it, some are corporate drivers like having an enterprise git client that has permissions handled thru MSDN. Sometimes it's a project management driver of having work items tied tightly to commit and builds, but with the added flexibility that OD brings to the table for free/minimal cost.

Hoping this help shine a little light into maybe why some people are crossing streams and using both VSTS and OD.

A lot of good points have been made already, but it really comes down to what you need. I would venture a lot of us started using Octopus before Release Management was really a thing.

We use VSTS for all our source control and builds and then all our deployments are handled through Octopus.

When we started evaluating tools, VSTS had nothing for deployments. Even now, they are still playing catch up to Octopus in feature set.

If you are doing true multi-tenanted and multi-environment deployments, I don't think VSTS really compares. We are using Octopus with around 30 tenants, some on Azure, some on premise. We deploy a mix of web and desktop apps. We are even using Octopus to deploy some legacy VB6 and winforms applications.

• Multi-Tenancy (critical for us)

  • VSTS added Deployment Groups a while ago which sound pretty similar to Octopus Environments before multi-tenancy was implemented. Before Octopus had true multi-tenancy (it's been around a while now), people would work around it by creating different environments per tenant, like "CustomerA - Dev", "CustomerA - Prod", etc. Now you just have your Dev/Test/Prod environments and each tenant can have variables scoped to those individual environments.

• Support

  • Documentation is excellent and it's really easy to get up and running.
  • The few times I've needed to contact someone at Octopus, they've answered very quickly and knowledgeably.

• Usability

  • Having the Octopus dashboard giving us an overview of all our projects is amazing. I don't know of anyway to do this in VSTS, without going into each individual project.
  • Octopus works great on a mobile device for checking deployment status and even starting new deployments.

• Community

  • Octopus works with their customers to understand what they want and they often release draft RFCs and have several times completely changed course based on customer feedback.

If we know what sort of applications you are deploying, and to what kinds of environments, we would be able to better tailor our responses.