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Observability is not plug and play

"Which is the best observability system?" It’s a question that crops up on observability and SRE forums with clockwork regularity. As often, the best answer is “it depends”. The observability market is full of great products, just like London is full of great restaurants. Asking which one is the best is not really that meaningful. It all depends on your needs, your tastes, your appetite and your wallet.

However, even if you do meet your perfect observability match, that is not the end of the story. It is just the beginning, and, like any relationship, it is something you need to work at. Observability is business-critical. It belongs in the same tier as your CRM, your finance platform and your customer support desk. None of these just works out of the box. Each rollout is a serious project that needs specialists who understand your business processes as well as the software.

What happened to my ROI?

Observability is no different. A "good" system is the starting point for good outcomes, not a guarantee. Enterprise software has a well-worn cycle of disillusionment. Management buy a shiny new system and expect it to solve every problem, without investing in training or shaping it around how the organisation actually works. The ROI never materialises, management conclude they need a new system. Rinse and repeat.

Observability systems are not a magic wand. They don't plug and play - even the ones that require zero instrumentation. A technology such as eBPF gives you remarkable visibility into the kernel and the network, but it knows nothing about your business logic. You need to do all the wiring to get the right data into the system. You also need quality and volume controls for your telemetry. Otherwise you will be firehosing terabytes of debug logs or redundant Kubernetes metrics into your observability system.

Strategy is your compass

No vendor can write your strategy for you, and few will try without a hefty consultancy fee attached. Before procuring a system you need to define an observability strategy to guide you through the maze. That strategy runs along two axes: resource constraints and technical requirements. Let’s examine them.

Resource constraints and expectations

Cost

This is obviously a highly important consideration but the cheapest system is not necessarily the best option in the long run. If the user experience doesn't suit your teams, adoption will stall, and the money you saved buys a tool nobody opens. Vendor costs are not always transparent and there can be significant gotchas hidden in the small print. There are third-party brokers who will haggle with vendors on your behalf, but they take their cut, and a lower price sometimes just buys a stripped-down product.

Timescales

Onboarding and trials are slow. You may shortlist half a dozen vendors, but trialling even one eats calendar time, along with the up-front effort of installation and instrumentation.

People

Who will administer the system and look after users and security? Who answers the alerts? Who builds the dashboards, keeps it running and watches the bill?

Expected outcomes

What problems are you trying to solve, and where does it hurt today? How will you evaluate the system and measure ROI? For some companies, observability is merely a cost centre, for others it is an investment and an accelerator. Without clear expected outcomes, you have no yardstick for the system's value.

Technical requirements

Observability platforms have now outgrown their APM roots. Depending on your business, you may need to weigh support for:

  • LLM observability
  • Agentic observability
  • Mobile observability
  • Anomaly detection
  • RUM
  • SIEM
  • Incident Management
  • Cost management
  • Cloud integration

Telemetry Volumes

One way or another, most vendors will tailor pricing around the volume of telemetry they ingest. How many GB of logs and traces do your systems generate each month? How many active metric series do they emit? Few teams can answer off the top of their heads, but you'll want those numbers in your pocket before you go shopping for a new stack.

Integrations

Will your vendor enable you to export data to third party systems – e.g. for SIEM, Incident Management, auditing or offline analysis? How good is the API? Does it expose every feature you'll need, or only a subset? Are there quotas or rate limits on what you can pull out?

Data retention and sovereignty

Many vendors will offer a default retention period of 30 or 60 days for your telemetry. Longer term retention periods can seriously bump up your observability bill. Some vendors' terms allow them to feed your telemetry into their machine-learning models. That may be unwelcome, and it could put you in breach of your statutory obligations or security policy. Make sure you read the small print. And if you ever leave, how easily can you take your historical data with you?

On-prem or cloud?

Can you bring your own storage? This is closely entwined with the sovereignty issues above but for many companies – especially those operating at very large volumes, it is also a critical factor in managing cost.

That list is far from exhaustive. You will have practical, technical and organisational questions of your own to add.

Tuning your Instrumentation

Software systems are unique combinations of code with millions of potential execution paths. The scope for logical errors is vast. Whilst many of those error conditions may be predictable, there are also plenty of unknowns and unknown unknowns. Your best defence is instrumentation that leaves a forensic trail for investigating future incidents.

Even the smartest AI cannot inject context and business-aware instrumentation into your codebase for you. It’s a process that involves input from professionals who understand your systems. Getting good telemetry out of your system also involves trudging through some pretty unglamorous groundwork, such as agreeing semantic conventions and telemetry standards. Instrumentation is a topic that could easily take up a whole book. We will just briefly cover four aspects:

  • Observability driven development
  • Arbitrarily Wide Structured Events
  • SLOs and alerting
  • Telemetry efficiency

Observability driven development

Observability-driven development (ODD) represents a shift in how engineering teams approach writing, testing, and shipping software. Instead of bolting instrumentation on afterwards, or tossing it over the wall to the SREs, ODD shifts it left into the earliest stages of development. This means examining code, evaluating how it may fail in production and then enriching your telemetry with the context that you will need for effective debugging.

Arbitrarily Wide Structured Events

Arbitrarily Wide Structured Events are an approach that has been energetically championed by Honeycomb. The idea is that telemetry should encapsulate a meaningful unit of work and that you should provide as much context as possible – so that an event may contain hundreds of key value pairs. Crafting these events is not technically difficult but it does require an up front investment of time and effort (plus a backend that can cope with the cardinality).

SLOs and alerting

Your observability system needs to align with the priorities and KPIs of your business. Large modern systems can run to thousands of nodes and endpoints. When the alerts start firing, you need to know which ones actually matter to your customers. Generally, this will mean defining SLOs and SLIs. The value of knowing that a CPU is running hot or that http 500 errors are up depends on their impact on the business. Some stacks support SLOs natively. Others leave you to roll your own from scripts, queries and alerts.

Telemetry efficiency

With an observability platform, the licence is only part of the cost. Ingestion and storage make up the rest, and both can be volatile. There are, however, levers you can pull to smooth out spikes and rein in volume. Telemetry pipelines have become a fixture of observability architectures. As well as transforming and filtering data, they can route lower-value telemetry to cheaper storage tiers. You don't have to throw more technology at the problem, though. Plain housekeeping works too: drop redundant logs and unused metrics and sample your traces.

An informed choice

An observability platform provides the data engine, but internal culture, engineering skill, and business context provide the steering wheel. Organisations that take a strategic view, invest in their teams and align telemetry with business outcomes will get the most out of their platforms. They will achieve greater ROI, better system performance and faster incident resolution regardless of which underlying product they choose. Most importantly, without an observability strategy, your procurement process is just a lucky dip.

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