DevOps - Tools and Technology

This post is the continuation of the DevOps - Operational model post in this blog.

We have seen how DevOps processes and organization can help the agility of IT, enabling a huge value for the business.

Let’s investigate the tools that smart organizations use to implement DevOps in the real world.

And let’s try to understand how, in addition to code management, the lifecycle of a sw application can be optimized by managing the infrastructure as code.

At the end of the day, we want to apply the following picture to the infrastructure as well.

 

Usually different environments are created to run application, often cloned for each Tenant (customer, project...): development, integration test, QA test, production, Disaster Recovery

The infrastructure must provide similar topology and functions, with different scale and HA requirements.

Those environments are sometimes used for few days, then they are no longer needed and the resources could be reused for next project.

If we were able to generate a new environment "end to end" when it is required, and to release all the resources to a shared pool, this  would help a lot in the optimization of resources usage.

The economy of scale provided by shared infrastructure and resource pools will add to the simplicity and speed of the operations.

The following picture shows the cycle of the builds (for both the sw application and the infrastructure) that optimizes the time and the resources.

From http://www.rightscale.com/blog/cloud-management-best-practices/continuous-integration-and-delivery-cloud-how-rightscale-does-it:

There are a number of tools and solutions that can help automating this process.

Some apply to specific phases, other to the end to end DevOps.

You can find a good list at http://en.wikipedia.org/wiki/Comparison_of_open-source_configuration_management_software

Also collaboration tools help the team(s) to work together for their own and the entire company's benefit: from http://www.collab.net/solutions/devops

The most used DevOps tools, as far as I know from direct experience and investigation, are jenkins, vagrant, puppet, chef.

Here is another possible chain of tools that cover the entire process:

From http://pages.cloudbees.com/rs/cloudbees/images/Continuous-Delivery-Infographic.pdf

Stateless Infrastructure (also known as SDDC)

We understood that the maximum benefit comes from being able to create and destroy environment on demand, allocate resources just when needed (we can also consider Disaster Recovery as a important use case in this scenario, but in that case you should also ensure that data have been replicated before the event).

Infrastructure as code is a core capability of DevOps that allows organizations to manage the scale and the speed with which environments need to be provisioned and configured to enable continuous delivery.

Evolving around the notion of infrastructure as code is the notion of software-defined environments.

Whereas infrastructure as code deals with capturing node definitions and configurations as code, software-defined environments use technologies that define entire systems made up of multiple nodes — not just their configurations, but also their definitions, topologies, roles, relationships, workloads and workload policies, and behavior.

Stateless Computing and Stateless Networking are important innovations that some vendors (Cisco could be considered a leader here) brought to the market in last 5 years.

Policy based configuration and the availability of software controllers for all the components of the architecture allow the separation of the modeling from the physical topology.

Servers

As an example, UCS servers (up to 160 in one management domain, but domains can be joined to share resources and policies) are stateless.

You can imagine each server (either a blade or a rack-mount server) as a dumb piece of iron, before you push its identity, its features (e.g. number, type and configuration of the network interfaces) and its behavior as a piece of configuration.

It is like adding the soul to a body.

Later you can move the same soul to a different body (maybe more powerful, such as from a 2-CPU server to a 4-CPU one). The new machine will be restarted as if it was the same.

This can be useful to recover a faulty server, to do DR but also to repurpose a server farm in few minutes (and eventually restore the previous state the day after).

The state (identity, features and behavior) is defined by a XML document that can be stored, versioned and managed as code in a repository (other than in the embedded UCS Manager).

This abstraction of the server from the actual machine makes the management easier and was the main factor for the incredible success of UCS as a server platform.

Networks

Similarly, in the networking domain, we have had a quantum leap in network management with Cisco ACI (Application Centric Infrastructure).

For those that have not met ACI yet, I have published a “ACI for Dummies” post.

In few words, ACI brings the management of physical and virtual networks together.

It has a very performant and scalable fabric, made of spine and leaf switches, that are managed by a software controller called APIC.

APIC also integrates the virtual switches in the different hypervisors, so that its policy model can be extended to the virtual end points.

A GUI is provided to manage APIC, but essentially you would drive it through the excellent open API offered to orchestration systems and - of course - DevOps tools.

XML (or JSON) artifacts can be stored in a repository as code, and pushing them to APIC will create your new Data Center on the fly.

You can create new Tenants with dedicated resources, or deploy the infrastructure for a new application in such a way that it is isolated (in terms of security, performances and stability) from others, though running on a shared infrastructure.

It would take just the time of a REST call, where you push the new policy to the controller.

And of course you could use the same templates in the different environments: development, integration test, QA test, production, Disaster Recovery

The previous generation of network devices (e.g. the Nexus family) can be managed in a DevOps scenario as well.

They offer API and have puppet agents onboard. And a version of the APIC controller has been created also for networks outside ACI (APIC-EM - https://developer.cisco.com/site/apic-em/discover/overview/).

The Cisco DevNet community prodives a lot of information and samples at https://developer.cisco.com/site/devnet/home/index.gsp

I wrote a short post on Ansible here: http://lucarelandini.blogspot.com/2015/05/a-powerful-devops-tool-ansible.html where a great recorded session from the Openstack Summit is linked.

You might be interested also in my post on DevOps, Docker and Cisco ACI.

 

The Elastic Cloud project - Methodology

This posts is the continuation of the post The Elastic Cloud Project - Architecture.

Here I will explain how we worked in the project: the sequence of activities that were required and the basic technologies we adopted.

The concepts are mostly explained by using pictures and screen shots, because an image is often worth 1000 words.

If you are interested in more detail, please add a comment or send me a message: I’ll be glad to provide detailed information.

To begin with, we had to:

• map the data model of the products used to understand what objects should be created, for a Tenant, in all the layers of the architecture
• create sequence diagrams to make the interaction clear to all the members of the team - and to the customer
• understand how the API exposed by Openstack Neutron and from Cisco APIC work, how they are invoked and what results they produce
• implement workflows in the CPO orchestrator to call the APIC controller and reuse the existing services in Cisco IAC
• integrate Hyper-V compute nodes in Openstack Nova
• create a new service in the Service Catalog to order the deployment of our 3 tiers application

Some detail about the activities above:

1 - Map the data model of the products used to understand what objects should be created, for a Tenant, in all the layers of the architecture

know that some of you still don’t know Cisco ACI… I promise that I will post a “ACI for dummies” soon.   :-)

  

This picture shows how concepts in Openstack Neutron map to concepts in Cisco ACI:

2 - Create sequence diagrams to make the interaction clear to all the members of the team

3 - Understand how the API exposed by Openstack Neutron and from Cisco APIC work, how they are invoked and what results they produce

This is a call to the Cisco APIC controller, using XML

This is a call to the Openstack Nova API, using JSON:

to do this, we used a REST client to learn the individual behavior and how the parameters need to be passed

a REST call is essentially a http call (GET or POST) where the body contains XML or JSON documents

some http headers are required to specify the content type and to hold security information (like a token for single sign on, that is returned by the authorization call and you need to resend in all the following calls to be recognized.

So we adopted Google Postman, that is a plugin for the Chrome browser (latest version is also released as a standalone application) to practice with the REST Calls then,after we learned how to manage them, we just copied the same content (plus the headers) into the “http call” tasks in the CPO workflow editor.

The XML or JSON variables that we passed are essentially static documents with some placeholders for current values, i.e. the Tenant name, the Network name, etc. were passed according to the user input.

Of course the XML elements tags are described in the APIC product documentation, you don’t have to reverse engineer their meaning   ;-)

Another way to get the XML ready to use is to export it from the APIC user interface: if you select an object that has been created already (either though the GUI or the API), you can export the corresponding XML definition:

This is how we copied the XML content from the test made in Postman and replaced some elements with placeholders for current values (that are variables in the workflow designer):

This is how the variable appear in the workflow instance viewer, after you have executed the process because a user ordered the service:

4 - Implement workflows in the CPO orchestrator to call the APIC controller and reuse the existing services in Cisco IAC

An example of the services that Cisco IAC provides out of the box.

They are also available through the API exposed by the product, so we created a custom workflow that reused some of the services as building block for our use case implementation.

his is the workflow editor, where we created the orchestration flow:

5 - integrate Hyper-V

At the time of this project, a direct support for Microsoft Hyper-V was not available in Openstack Nova.

But a free library was available from Cloudbase, so we decided to install it on our Hyper-V serverso that the virtual data center (VDC) we had created in Cisco IAC thanks to the integration with Openstack could use also Hyper-V resources to provision the VM.

More detail on the integration can be found here: http://www.cloudbase.it/openstack/

In the current Openstack release (Juno), Hyper-V servers are managed directly.

6 - create a new service in the Service Catalog

Conclusion

This project had a complexity that derived from being the among the first teams in the world to try the integration of so many disparate technologies: Cisco software products for Service Catalog and Orchestration, three hypervisors (ESXi, Hyper-V, and KVM), physical networks (Cisco ACI) and virtual networks in all the hypervisors, Openstack.

I didn't tell you, but also load balancers and firewalls were integrated.

Maybe I will post some detail about the Layer 4 - Layer 7 service chaining in the next weeks.

We had to learn the concepts before learning the products. Actually theinvestigation of the API and their integration was the easiest part... and was also fun for my ancient memory of programmer   :-)

Now, with the current release of the products involved in this project, everything would be much easier.

Their features are more complete (actually the integration of the Neutron API in the management of Virtual Data Centers in ACI was fed back to our engineering during this project).

Skills available on the field are deeper and widespread.

I've already implemented the same use case with alternative architectures twice.

Cisco UCS Director was used once, replacing the IAC orchestration and pre-built services.

And, in another variation, the Openstack API were integrated directly instead of reusing the existing services that manage the Openstack VDC in IAC.

Just to have more fun... ;-)

The Elastic Cloud Project - Architecture

This posts is the continuation of The Elastic Cloud Project post.

There is a team at Cisco, called System Development Unit, that creates reference architectures and CVD (Cisco Validated Design).

They work with the product Business Units to define the best way to approach common use cases with the best technology.

But at the time of this project, they hadn’t completed their job yet (some of the products were not even released).

So we had to invent the solution based on our understanding of the end to end architecture and integrate the technologies on the field.

As I explained before, the most important components were:

- servers - Cisco UCS blades and rack mount servers

- network - Cisco ACI fabric, including the APIC software controller

- virtualization - ESXi, Hyper-V, KVM

- cloud and orchestration software - Cisco PSC and CPO, Openstack (PSC and CPO, plus pre-built services, make up Cisco Intelligent Automation - IAC)

IAC can integrate different “element managers” in the datacenter, so that their resources are used to deliver the cloud services (e.g. single VM or Virtual Data Centers - VDC).

Element managers include vmware vCenter and Openstack, so a end user can get a VDC based on one of these platforms.

There is a autometed process in IAC, called CloudSync, that discovers all the resources available in the element managers and allow the admin to select those he wants to use to provision services (resource management and lifecycle management are amongst the features of the product).

The ACI architecture

I will cover it in detail in one of next posts, but essentially ACI (http://www.cisco.com/c/en/us/solutions/data-center-virtualization/application-centric-infrastructure/index.html), that stands for Application Centric Infrastructure, is a holistic architecture with centralized automation and policy-driven application profiles. ACI delivers software flexibility with the scalability of hardware performance. 

Cisco ACI consists of:

• The new Cisco Nexus 9000 Series Switches
• A centralized policy management and Cisco Application Policy Infrastructure Controller (APIC)
• A Cisco Application Virtual Switch (AVS) for the virtual network edge
• Software and hardware innovations
• Integrated physical and virtual infrastructure
• An open ecosystem of network, storage, management, and orchestration vendors
  
  
  

The policies that you create in the software controller (APIC) are enforced by the fabric, including physical and virtual networks.

You describe the behavior your application need from the network, non the configuration you need.

This is easier for the application designer, in the collaboration with network managers, because it can be graphically described by the Application Network Profile.

A profile contains End Point Groups (EPG, representing deployment units of the application: both physical and virtual servers) and Contracts (that define the way EPG can communicate).

A profile can be saved as a XML or JSON document, stored in a repository, participate in the Devops lifecycle, used to clone a environment and managed by any orchestrator.

ACI is integrated with the main virtualization platforms (ESXi, Hyper-V, KVM).

To deploy our 3 tier application on 3 different hypervisors, we had to manage vmware and Openstack separately - but in a single process, because everything should be provisioned with a single click.

Initially we based our custom implementation of the new service on the standard IAC services, using them as building blocks.

So we had not to implement the code to create a network, create a VDC, create a Virtual Server, trigger CloudSync, integrate the virtual network with the hardware fabric.

This sequence of operations was common to the Openstack environment and the vmware environment.

The main workflow was built with two parallel branches, the Openstack branch (creating 2 web servers on one network and 1 application server on anothernetwork) and the vmware branch (doing the same for the database tier).

The problem is that the integration of IAC with Openstack, in the 4.0 release that we used at that time, only deals with Nova - that, in turn, manages both KVM and Hyper-V servers.

No Neutron integration was available out of the box, hence no virtual networks for the Openstack based VDC.

So we built the Neutron integration form scratch (implementing direct REST calls to the Neutron API) to create the networks.

The ACI plugin for Neutron does the rest: it talks to the APIC controller to create the corresponding EPG (End Point Group).

This implementation has been fed back to IAC 4.1 by the Cisco engineering, so in the current release it is available out of the box.

Solution for Openstack

A plugin distributed by Cisco ACI was installed in Openstack Neutron, to allow it to integrate into the APIC controller.

This is transparent to the Openstack user, that goes on working in the usual way: create network, create router, create VM instances.

Instructions are sent by Openstack to APIC, so that the corresponding constructs are deployed in the APIC data model (Application Profiles, End Point Groups, Contracts).

The orchestrator can then use these objects to create a specific application logic, spanning the heterogeneous server farms and allowing networks in KVM to connect to networks in ESXi and Hyper-V.

So the workflow that we built only needed to work with the native API in Openstack.

Logical flow:

— web tier --

create a virtual network for the web tier via Neutron API

     the Neutron plugin for ACI calls - implicitly - the APIC controller and creates a corresponding EPG.

     the Neutron plugin for OVS creates a virtual network in the hypervisor's virtual switch

trigger the CloudSync process, so that the new network is discovered and attached to the VDC

create a VM for the web server and attach it to the network created for the web tier

     this was initially done by reusing the existing IAC service “Provision a new VM"

— application server tier — 

create a virtual network for the app tier via Neutron API

     the Neutron plugin for ACI calls - implicitly - the APIC controller and creates a corresponding EPG.

     the Neutron plugin for OVS creates a virtual network in the hypervisor's virtual switch

trigger the CloudSync process, so that the new network is discovered and attached to the VDC

create a VM for the application server and attach it to the network created for the app tier

     this was initially done by reusing the existing IAC service “Provision a new VM"

— connect the tiers via the controller —  

connect the two EPG with a Contract, that specifies the business rules of the application to be deployed

     this is done via the APIC Controller’s API, creating the Application Profile for the new application in the right Tenant

Solution for vmware

The APIC controller has a direct integration with vmware vCenter, so the integration is slightly different from the Openstack case:

The operations are performed directly against the APIC API and, when you create a EPG there, APIC uses the vCenter integration to create a corresponding virtual network (a Port Group) in the Distributed Virtual Switch.

So we added a branch to the main process to operate on APIC and vCenter, to complete the deployment of the 3 tier application with the database tier. 

Logical flow:

— database server tier — 

call the APIC REST interface, implementing the right sequence (authentication, create Tenant, Bridge Domain, End Point Group, Application Network Profile).

     specifically a EPG for the database tier is created in the APIC data model, and this triggers the creation of a port group in vCenter.

trigger the CloudSync process, so that the new network is discovered and attached to the VDC

create a VM for the database server and attach it to the network created for the app tier

     this was initially done by reusing the existing IAC service “Provision a new VM"

Service Chaining

The communication between End Point Groups can be enriched by adding network services: load balancing, firewalling, etc.

L4-L7 services are managed by APIC by calling external devices, that could be either physical or virtual.

This automation is based on the availability of device packages (set of scripts for the target device), and a protocol (Opflex) has been defined to allow the declarative model supported by ACI being adopted by all 3rd party L4-L7devices. 

Cisco and its partners are working through the IETF and open source community to standardize OpFlex and provide a reference implementation.


In next post, I will describe the methodology we used to integrate the single pieces of the architecture, how we learned to use the API exposed by the target systems (APIC and Openstack) and to insert these calls into the orchestration flow.

Link to next post: The Elastic Cloud Project - Methodology

The Elastic Cloud Project

The Elastic Cloud was a pilot project that I led as a software architect for a customer.

They wanted to evaluate the complexity and the overal quality of a end to end solution provided by Cisco for Cloud Computing.

So we built a complete infrastructure, including hardware and software, for a public cloud.

The number of use case was limited, and I will tell you about the most curious one.

When I was told about the requirement, I thought it didn’t make sense in the real world… but later I understood the rationale  :-)

The request was to deploy a three tier application, with a single click, provisioning also all the needed infrastructure at the same time: (virtual) servers, network and storage.

So this is an example of software defined datacenter, not only SDN but the entire stack: from hardware to the sw application. 

The strange aspect of this requirement is that every tier of the application should run on a different virtualization platform: web servers on KVM, application servers on Hyper-V, database server on ESXi.

It was a technical demonstration, sure, but it also reflected a real world use case. They have some customers that, for legacy applications, have certification constraints that mandate a specific hypervisor for at least one part of the application. So the deployment cannot be standardized on a single platform.

Our customer wanted to verify that Cisco is able to orchestrate a multi vendor infrastructure and that the advantages of stateless computing (I will explain it in a different post, but essentially it is joining SDN with the quality of a hardware infrastructure) are not compromised by the etherogeneity of the virtualization layer.

They said that no other vendor was able to implement the entire use case on the 3 major hypervisors together.

This is a very high level description of the use case:

We decided to implement the self service process in the portal provided by Cisco Prime Service Catalog.

The orchestration layer was Cisco Process Orchestrator, interfacing with Openstack and vmware vCenter directly.

Openstack had compute nodes running KVM and Hyper-V.

Virtual networks were created, on demand, in the virtual switches in each hypervisor and then joined by the physical network connecting the virtualized servers.

The configuration of the network was done through the APIC software controller, that is part of the Cisco ACI architecture (Application Centric Infrastructure).

 

There is a solution, offered by Cisco, that provides cloud services out of the box.

It is called Intelligent Automation for Cloud (IAC) and it is based on the Prime Service Catalog (PSC) as a front end, the Cisco Process Orchestrator (CPO) and prebuilt services created by the Cisco engineering.

IAC integrates your infrastructure by interfacing with vCenter, vCD, Openstack and other so called “element managers” and has all the tools to manage the resources lifecycle.

We decided to reuse some of the existing services as building blocks, wrapping them in a custom process implementing the logic of the specific use case.

So we created a workflow in the visual editor of CPO that invokes the existing atomic services: create a virtual network, create a VDC (virtual data center), create a virtual server.

Then we added explicit calls to the API of the target systems that were not integrated in IAC: the APIC Controller for the ACI fabric, Neutron as the manager of the networking in Openstack (the 4.0 release of IAC only managed Nova for provisioning VMs in Openstack, now also Neutron is integrated in IAC 4.1).

So the effort in this project was only dedicated to understanding the overall logic of the use case and implementing the needed API calls.

It was not particularly difficult, because the target API are all based on a REST interface (both for APIC and Neutron) so invoking them from CPO was a kids’ play.

We created a process with 3 branches, one for each tier of the application, creating all the needed networks and virtual machines, then “plumbing” all together with the ACI fabric through the API of the APIC controller.

We were forerunners, trying to implement a exotic use case before the Business Units looked at it… now everything is available out of the box    ;-)

So we faced the following issues:

• Lack of reference architecture and some products features.
• Dispersed team (time zones and location) made the coordination difficult.
• Fragmented skills: none of us had the complete knowledge of all the products and technologies, due to the amount of innovation involved. 
• Multitasking: many of us were working part time, engaged on different projects.
• Generous support from individuals and organizations in the company, but limited governance
• Products limitations discovered in progress (and solved with... fantasy)
• Usage of beta code and daily builds for some of the products
• Limited documentation available  

In next post I will tell the entire story and how we were able to demonstrate the main concepts:

• Cisco ACI is one of the best solutions for SDN and is not limited to software overlay only
• Cisco has a end to end solution for cloud, including sw and hw and people that can design the architecture
• Open source solutions can be easily integrated into a commercial architecture, providing additional value
• The contribution Cisco provided to Openstack allows customers to manage our network fabric from Neutron seamless

Link to next post: The Elastic Cloud Project - Architecture