TELEICU/Current state assessment - Revision history

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← Older revision		Revision as of 08:39, 6 July 2026
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	All three factors compound: unreliable connectivity makes updates harder, tampering makes state unpredictable, and OS fragmentation makes every node slightly different. The migration strategy targets all three simultaneously by enforcing a single, immutable or pull-reconciled configuration across a uniform OS baseline.		All three factors compound: unreliable connectivity makes updates harder, tampering makes state unpredictable, and OS fragmentation makes every node slightly different. The migration strategy targets all three simultaneously by enforcing a single, immutable or pull-reconciled configuration across a uniform OS baseline.

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{{Doc header
|type=concept
|domain=teleicu
|title=Current state assessment
|order=3
}}

The current TELEICU deployment across 200+ sites suffers from three systemic reliability factors. This page documents them so the upgrade targets them specifically.

== Factor 1: Power and internet disruption ==

Sites in semi-urban and rural areas experience unreliable grid power and internet connectivity.

'''Impact:'''
- Nodes go offline without graceful shutdown, risking data corruption on the underlying filesystem
- Configuration pull agents (once deployed) will have irregular check-in windows
- Monitoring must account for nodes that are expected to be offline for hours at a time
- Alerting must distinguish between a genuinely failed node and one that is simply disconnected

== Factor 2: Tampering and configuration drift ==

Hospital PCs are physically accessible to local staff. This has led to:

- Cloudflare tunnel credentials being modified or replaced
- Docker Compose files being hand-edited, breaking expected service definitions
- System configuration (networking, firewall rules) being changed without change control
- No audit trail for who made what change

'''Impact:'''
- Declared state and actual state diverge silently
- Support calls increase as nodes exhibit non-standard behavior
- Security posture degrades as tunnel creds may be compromised

Both upgrade paths address this differently:
- '''Ansible''': ansible-pull reverts drift on each run (soft guarantee — drift can exist between pull intervals)
- '''NixOS''': Immutable /etc — tampering is impossible without rebooting to a different generation (hard guarantee)

== Factor 3: OS security and maintenance gaps ==

The fleet is fragmented across three Ubuntu versions:

- Ubuntu 20.04 — several nodes, nearing or past EOL for some packages
- Ubuntu 22.04 — the majority
- Ubuntu 24.04 — newer additions

'''Impact:'''
- No consistent patch cadence across the fleet
- Security patches applied ad-hoc or not at all
- Ansible roles / NixOS modules must handle version-specific differences
- Upgrade path to a single baseline requires either OS reinstall (NixOS) or an in-place upgrade playbook (Ansible)

== Summary ==

All three factors compound: unreliable connectivity makes updates harder, tampering makes state unpredictable, and OS fragmentation makes every node slightly different. The migration strategy targets all three simultaneously by enforcing a single, immutable or pull-reconciled configuration across a uniform OS baseline.

{{Related}}

← Older revision		Revision as of 09:05, 6 July 2026
Line 13:		Line 13:

	'''Impact:'''		'''Impact:'''
	- Nodes go offline without graceful shutdown, risking data corruption on the underlying filesystem		* Nodes go offline without graceful shutdown, risking data corruption on the underlying filesystem
	- Configuration pull agents (once deployed) will have irregular check-in windows		* Configuration pull agents (once deployed) will have irregular check-in windows
	- Monitoring must account for nodes that are expected to be offline for hours at a time		* Monitoring must account for nodes that are expected to be offline for hours at a time
	- Alerting must distinguish between a genuinely failed node and one that is simply disconnected		* Alerting must distinguish between a genuinely failed node and one that is simply disconnected

	== Factor 2: Tampering and configuration drift ==		== Factor 2: Tampering and configuration drift ==
Line 22:		Line 22:
	Hospital PCs are physically accessible to local staff. This has led to:		Hospital PCs are physically accessible to local staff. This has led to:

	- Cloudflare tunnel credentials being modified or replaced		* Cloudflare tunnel credentials being modified or replaced
	- Docker Compose files being hand-edited, breaking expected service definitions		* Docker Compose files being hand-edited, breaking expected service definitions
	- System configuration (networking, firewall rules) being changed without change control		* System configuration (networking, firewall rules) being changed without change control
	- No audit trail for who made what change		* No audit trail for who made what change

	'''Impact:'''		'''Impact:'''
	- Declared state and actual state diverge silently		* Declared state and actual state diverge silently
	- Support calls increase as nodes exhibit non-standard behavior		* Support calls increase as nodes exhibit non-standard behavior
	- Security posture degrades as tunnel creds may be compromised		* Security posture degrades as tunnel creds may be compromised

	Both upgrade paths address this differently:		Both upgrade paths address this differently:
	- '''Ansible''': ansible-pull reverts drift on each run (soft guarantee — drift can exist between pull intervals)		* '''Ansible''': ansible-pull reverts drift on each run (soft guarantee — drift can exist between pull intervals)
	- '''NixOS''': Immutable /etc — tampering is impossible without rebooting to a different generation (hard guarantee)		* '''NixOS''': Immutable /etc — tampering is impossible without rebooting to a different generation (hard guarantee)

	== Factor 3: OS security and maintenance gaps ==		== Factor 3: OS security and maintenance gaps ==
Line 40:		Line 40:
	The fleet is fragmented across three Ubuntu versions:		The fleet is fragmented across three Ubuntu versions:

	- Ubuntu 20.04 — several nodes, nearing or past EOL for some packages		* Ubuntu 20.04 — several nodes, nearing or past EOL for some packages
	- Ubuntu 22.04 — the majority		* Ubuntu 22.04 — the majority
	- Ubuntu 24.04 — newer additions		* Ubuntu 24.04 — newer additions

	'''Impact:'''		'''Impact:'''
	- No consistent patch cadence across the fleet		* No consistent patch cadence across the fleet
	- Security patches applied ad-hoc or not at all		* Security patches applied ad-hoc or not at all
	- Ansible roles / NixOS modules must handle version-specific differences		* Ansible roles / NixOS modules must handle version-specific differences
	- Upgrade path to a single baseline requires either OS reinstall (NixOS) or an in-place upgrade playbook (Ansible)		* Upgrade path to a single baseline requires either OS reinstall (NixOS) or an in-place upgrade playbook (Ansible)

	== Summary ==		== Summary ==