devopsy.kinsta.cloud

Tag: virtual networking

  • Focus on High-Level Policy Requirements to Accelerate Network Processes for DevOps

    Focus on High-Level Policy Requirements to Accelerate Network Processes for DevOps

    Network operations traditionally has been the missing piece in DevOps processes. It’s not difficult to see why. Network management has lagged behind server and workload automation. Updating network policies and configurations typically requires a great deal of analysis, testing and time, undermining the goal of DevOps agility. But once we shift how network devices are administered and how changes are validated, there are emerging ways to incorporate network updates and policies into DevNetOps processes through automation.

    Shift the Focus to Policies, Not Configurations

    DevOps has taken off, thanks in part to the ability of virtual networking and software defined networks (SDN) to automate the placement of workloads, establish connectivity and deliver Layer 4 to 7 services in a few minutes. But virtually all network policy updates, particularly those addressed in the underlay, were constrained by having to reconfigure individual network devices through traditional management platforms or command line interfaces (CLI). New application deployments may require new network paths, access to cloud resources, punching holes in firewalls, etc. There was no way to automate these policy-related tasks through existing network management platforms, and DevOps processes were limited to simple changes that could be made in the overlay network.

    Figure 1: The CLI management model and box-by-box management, in general, do not facilitate DevOps processes, which require higher level policy specifications and requirements. DevOps requires the automation of such policy analysis and verification.

    What’s wrong with updating individual network devices through CLI? Network administration is hampered by the inherent nature of IP networks individual devices never have a holistic end-to-end view of network policies and behavior. They are usually configured to know what to do with traffic locally, when to drop it and when to forward it to which nearest neighbor. This is not how policy requirements are formed (see Figure 1).

    If a new DevOps deployment needs to ensure a rack in Data Center 1 can reach a rack in Data Center 2 through a specific secure gateway, then to a cloud-hosted database and return traffic appropriately, then we need a much broader, path-based view than any individual device or CLI can give us. If we are going to automate any of this analysis or verification, we are going to need a solution that maps our intended policy requirements to network implementations across many devices.

    Intent-Based Networking Aligns With Policies and Intent

    This is where intent-based networking (IBN) can help. IBN can help bridge our application policy requirements with the network design and configuration. It can allow us to verify if a particular policy requirement is supported in the network currently or help with a path-oriented search to quickly identify which devices need to be updated to deliver the particular policy. Changes, such as updating a firewall rule, ultimately may still be made to a single device through a CLI, but we have accelerated the analysis if the policy is currently supported, what changes need to be made and how such a change may adversely affect other existing policies and requirements.

    For example, it may be an enormous benefit to application development teams prior to deploying a new workload, to be able to determine if connectivity from our Rack 1 servers to a remote database is available for new traffic requirements. Typically, this might involve a request to the network team, which would have to analyze the policy requirements or arrange for a test scenario. A trouble ticket request such as this would take more than just a few minutes, even if the network team could jump right on it.

    Application Team Self-Service

    Imagine instead the application team could self-service their request by querying an IBN system that could immediately verify the implementation of the policy. Perhaps the application team could use a simple internal messaging platform such as Slack to specify their policy requirement and get an immediate answer without further analysis by the network team. They wouldn’t even need to learn the GUI or capabilities of the underlying IBN platform with a Slack messaging front-end.

    An IBN solution gives teams the power to avoid thinking in terms of individual device rules and opens the door to end-to-end automated policy analysis for the first time. Application teams could never be expected to understand firewall configurations or be able to self-service their queries about those capabilities, but they can think in terms of high-level application policy requirements and end-to-end path behavior, which IBN platforms can deliver (see Figure 2).

    Figure 2: A sample policy query is constructed in the top bar, as the IBN platform shows a number of available paths between data centers that map to the policy requirements.

    Automating Network Verification

    To further accelerate key network policy changes required for DevOps processes, imagine updates are required to individual devices in the underlay network. Not only can those changes be identified nearly immediately now through IBN, but also the verification that the changes were made correctly and didn’t adversely affect any other applications or policy requirements can be completely automated. These IT tasks of analysis and verification were usually the most manual and time-intensive in the network operations workflow. But now that much of the workflow can be automated, DevOps can benefit greatly.

    The verification process would consist of a long list of existing policy requirements that were already in place and implemented. After a proposed change to network configurations, all of those policies could be analyzed quickly to determine if the new update adversely affected any prior requirements, preventing rollbacks or potential security or compliance breaches.

    The question naturally arises, What is really enabling this shift in network operations from a box-by-box focus to an end-to-end, path-oriented policy focus? IBN platforms have generally replicated much of the analytical intelligence of network engineers to determine overall behavior from analyzing individual device configurations and state information. Much of this intelligence is based on mathematical models of the running network in software and much less so now on analyzing live traffic under limited scenarios. This analysis of the mathematical model in IBN platforms now can provide definitive verification of policy requirements for the first time, and even identify configuration errors long before they can cause loss of service or an outage.

    The key to accelerating network analysis and updates in support of DevOps processes is to shift focus up from individual box-by-box device management and CLI interfaces to focus on end-to-end network behaviors that align with application policy requirements. Application team self-service for many policy-related network requests and automation of network verification tasks are just a few of the benefits for DevOps teams that IBN can deliver today and into the future.

    — Chiara Regale

  • APIs and DevOps

    APIs and DevOps

    As always, there are interesting trends in DevOps, and I wanted to point out one that is starting to bother me: the “API economy,” and how it impacts DevOps decision-makers.

    Traditional infrastructure—SAN, LAN, physical systems, etc.—were generally controlled the best from the command line. While there are a million of them, Cisco IOS is probably the one that you’ll remember best (or you stopped using to read this—just depends upon the shop). When large-scale automation started, these command lines became a bit problematic. After all, scripting was possible, but painful, and often had non-portable hardcoded values.

    Virtualization, and later cloud—and even later SDN and NFV—all made this better, but on a layer over the top of (and normally not well integrated with) the physical layer. Years ago I bemoaned that we had doubled the workload of operations by re-implementing what was already implemented at the physical layer. So we were configuring the physical—even for cloud you have to get to the cloud—and then configuring the virtual.

    Then “Software Devs as Kingmakers” came along, followed by “the API Economy,” and finally we started to see some serious attention paid to APIs by infrastructure vendors that should have done so long ago (some former employers of mine might belong in this group).

    Here is the thing: There is a difference between having an API and having an API that is useful. When shopping for solutions, be they physical or software, don’t allow APIs to be a check box because it’s “the API Economy.” And don’t assume that an API useful to DEVops is what is needed to automate infrastructure. Monitoring APIs—particularly ones that provide you detailed information about an app as it runs—are useful to DEVops, and assuming you have tools that are or can be integrated, might provide value to devOPS.

    But monitoring is not management. devOPS is increasingly automated, and increasingly needs viable APIs that can help them deploy/configure infrastructure. Vendors are responding, but the quality of APIs at this point in time varies widely. So make certain that evaluation looks at APIs available with an eye to suitability to task. devOPS needs management and might be able to use monitoring, while DEVops generally needs monitoring and has little use for management.

    This is not 100% true of course, there are a billion different shops, most doing things in slightly different ways, but think of storage (because it can be done in few enough words to fit in a blog)… An app needs access to storage, ways to be notified of storage space limitations, and possibly to metadata. Operations needs to provision, migrate, backup, replicate… The list goes on. These all contribute to the availability and quality of the application, and are all DevOps, but the focus is different. And having a simple “number of blocks free” API will not help with the DevOPS needs even if it helps developers manage a piece of the application.

    But we have more options than we ever did before! So fear not, just watch what your prospective vendors are doing, and check in with long-term vendors on occasion, too—because things are constantly changing, nearly always improving.

    And keep rocking it. Presumably you are working this out already, knowingly or not, or you wouldn’t have time to read this blog.

    — Don Macvittie

  • Containers: All Your Base are Belong to Us

    Containers: All Your Base are Belong to Us

    The world is still changing. No surprise there, but the direction and velocity have been modified by the growth of container usage. Back in 2015, we at devopsy.kinsta.cloud showcased a survey we performed that said container usage was staged to take off. That it did, with a vengeance. No matter the category—pilot programs, test, production—it seems to have a greater penetration each year.

    And why not? There are a whole collection of benefits to containers—smaller footprint than VMs, more portable than cloud instances, more agile than … well, any of the alternatives. And the weaknesses—the use (and abuse) of IPTables and persistent problems with persistent storage—are being addressed at a rapid clip.

    But It’s Not All Roses

    Sorry to say that there is, as always, a fly in the ointment. We have to identify weaknesses in new architectures to plan for them and overcome them. And container infrastructure is not immune to this process. Nothing is perfect.

    The first problem is with overall security. Your container management system is now the center of the world. A single point of penetration that could yield dozens to thousands of infected servers. It is like a magnet to ne’er-do-wells. Protect it, lock it down, follow advice on Container Journal and Security Boulevard about how to keep your system as protected as possible.

    That was the easy one. We have a ton of experience protecting important central systems.

    The more difficult ones all revolve around your physical infrastructure and where it meets your virtual container infrastructure. Look at all the boxes in your data center and the services they provide, then map out how those services integrate with your containers. Once you’ve mapped them, work the mappings into your DevOps projects. Load balancing and storage provisioning are two areas in which what a traditional DC does is duplicated inside the container environment, and where that processing is to occur should be a conscious choice about what is best for the application, not a decision based on what is easiest/in front of you.

    It is an (arguably) bigger issue with storage. Just because the container can grow or shrink its internal storage does not make it the right place to position a fair selection of your data. Think about what will be needed in the future—with or without the application that this container or container set represents—and make a conscious choice about what is ephemeral data that can go away should an instance die versus what is needed long-term. Work those choices into DevOps processes. It can be a pain to access persistent data that is remote to a container, so make the painful parts automated via your DevOps processes.

    Both of these problems are compounded in most (but not all) cloud environments. Too much cloud functionality is designed to lock users in. While that has been a standard practice in IT for decades, the problem with containers is that they are inherently portable. Build them to be so. Yes, lock-in functionality always brings benefits, but mobility lets a team choose where best to deploy a container system with each inflection point (purposely being vague here—a highly agile/DevOps shop could have daily inflection points, while a single team just piloting containers in their DevOps environment may only have them on occasion when something large changes with the system). Should something change at a preferred cloud vendor that makes them no longer preferred, the fewer modifications required to move to another platform the better. So building default container/container management into the DevOps toolchain is preferred to building in vendor-specific options when a choice is available. Storage is an easy one to point at and say “choice might not be available.” Allocating disk is not very portable between platforms, but if that’s one of only a handful of things that must change, portability is still an option.

    In short, containers are coming, and they’re coming fast. Build them into your DevOps toolchain as portable solutions that automate the worst of the speed bumps. Make conscious choices about where infrastructure-based functionality should reside, and implement based upon those choices.

    And keep rocking it. If moving from any other environment (with the arguable exception of cloud), containers will be faster to spin up and to spin down. Just address the issues before they hit you, and all will be well.

    — Don Macvittie