Linux Systems Administrator / DevOps Engineer

# Linux Systems Administrator / DevOps Engineer

**Company:** Dataphone

**Employment:** Full-Time

**Location:** Remote

## About Dataphone

Dataphone operates a large-scale communications platform providing VoIP, PBX, Contact Center, SMS, AI voice, and business communication solutions.

Our production environment includes Linux servers, Node.js/TypeScript applications, PM2, NGINX, PostgreSQL, FreeSWITCH, OpenSIPS, Docker, monitoring systems, and multiple customer-facing services.

We are looking for a hands-on **Linux Systems Administrator / DevOps Engineer** who can take ownership of this infrastructure and help us keep it reliable, secure, and scalable.

## Responsibilities

### Linux Server Administration

• Manage production Debian/Ubuntu Linux servers
• Server provisioning, configuration, upgrades, patching, and hardening
• Manage CPU, memory, storage, processes, services, and networking
• Troubleshoot production outages and performance problems
• Manage SSH, users, permissions, sudo, and security
• Monitor server health and capacity
• Perform server migrations and maintenance with minimal downtime
• Maintain backups and disaster-recovery procedures

### Node.js / TypeScript Application Infrastructure

• Deploy and maintain Node.js/TypeScript applications
• Manage applications running under **PM2**
• Troubleshoot application crashes and memory leaks
• Monitor PM2 processes, CPU, memory, restarts, and logs
• Configure PM2 clusters and process management
• Perform application deployments and rollbacks
• Troubleshoot application/server interactions
• Work with developers to resolve production issues
• Help establish standardized deployment procedures

You do **not** need to be a full-time application developer, but you must understand how Node.js applications run in production and be comfortable troubleshooting them.

### NGINX

• Configure and maintain NGINX
• Reverse proxy configuration
• SSL/TLS certificates
• HTTP/HTTPS routing
• Load balancing
• WebSocket proxying
• Connection and timeout configuration
• Troubleshoot 4xx/5xx errors
• Configure security headers and access controls
• Review NGINX access/error logs
• Optimize NGINX for production traffic

### PostgreSQL

• Manage production PostgreSQL servers
• Monitor database health and performance
• Troubleshoot connection issues
• Monitor CPU, memory, disk, locks, and connections
• Perform backups and restores
• Understand indexes and basic query performance
• Assist developers with database-related production issues
• Support replication/high-availability configurations

### VoIP Infrastructure

• Maintain and troubleshoot **FreeSWITCH**
• Maintain and troubleshoot **OpenSIPS**
• Troubleshoot SIP registration and call-routing problems
• Analyze SIP/RTP traffic
• Use Wireshark, tcpdump, and sngrep
• Troubleshoot NAT, RTP, codecs, packet loss, and latency
• Monitor telecom infrastructure
• Assist with scaling and load balancing

### Docker

• Manage Docker containers
• Troubleshoot containers that fail or restart
• Manage Docker networking and volumes
• Monitor container resources
• Maintain Docker-based production services
• Assist with containerizing additional applications

### Monitoring & Logging

Maintain and improve monitoring across the infrastructure.

Experience with:

• Grafana
• Prometheus
• Loki
• Netdata
• Linux system logs
• NGINX logs
• PM2 logs
• Application logs
• PostgreSQL monitoring
• FreeSWITCH/OpenSIPS logs

The goal is to identify infrastructure problems **before they become customer-impacting outages**.

### Networking

Strong understanding of:

• TCP/IP
• DNS
• HTTP/HTTPS
• WebSockets
• TCP/UDP
• NAT
• Firewalls
• Routing
• VLANs
• Public/private networking
• SIP/RTP networking

### Automation

• Bash scripting
• Python and/or JavaScript/TypeScript scripting
• Ansible or similar configuration-management tools
• Git
• Automate repetitive server-management tasks
• Create scripts for monitoring, deployment, maintenance, and troubleshooting

## Production Troubleshooting

This role requires someone who can independently investigate problems such as:

• Node.js application repeatedly crashing
• PM2 process consuming excessive memory
• NGINX returning 502/504 errors
• WebSocket connections dropping
• PostgreSQL connections becoming exhausted
• Server running out of disk space
• FreeSWITCH CPU suddenly increasing
• SIP registrations failing
• Calls connecting without audio
• OpenSIPS routing failures
• Docker containers repeatedly restarting
• Network latency or packet loss
• SSL certificate expiration
• High server load
• Application deployment causing an outage

The expectation is:

**Detect → Investigate → Identify root cause → Fix → Verify → Document**

## Required Skills

### Must Have

• 3+ years Linux administration / DevOps experience
• Strong Debian/Ubuntu experience
• Strong Linux troubleshooting
• NGINX
• Node.js production environments
• PM2
• PostgreSQL
• Docker
• Networking
• Bash scripting
• Git
• Monitoring/logging
• Strong production troubleshooting ability

### Preferred

• FreeSWITCH
• OpenSIPS
• FusionPBX
• SIP/RTP
• Wireshark
• sngrep
• Prometheus
• Grafana
• Loki
• Netdata
• Ansible
• Redis
• WebSockets
• CI/CD
• OVH/Vultr/AWS infrastructure

## Ideal Candidate

The ideal candidate is **not someone who only knows how to follow a checklist**.

We need someone who can receive a problem such as:

> "The API is slow and customers are getting intermittent 502 errors."

…and independently work through:

**NGINX → PM2 → Node.js → PostgreSQL → Linux → Network**

to determine where the actual problem is.

You should be comfortable logging into a server, examining processes and logs, running diagnostics, making a controlled change, verifying the result, and documenting the solution.

## Work Style

We are looking for someone who:

• Takes ownership
• Works independently
• Is a strong problem solver
• Doesn't require constant supervision
• Can work during production incidents
• Communicates clearly
• Documents changes
• Understands the importance of uptime
• Knows when to escalate an issue
• Continuously improves infrastructure rather than simply maintaining it

## Technical Assessment

Candidates may be required to complete a practical assessment covering:

1. Linux troubleshooting

2. NGINX configuration

3. PM2/Node.js troubleshooting

4. PostgreSQL troubleshooting

5. Networking

6. Docker

7. FreeSWITCH/OpenSIPS fundamentals

8. Monitoring and log analysis

The assessment will focus on **real-world troubleshooting and problem-solving rather than memorization**.

## Compensation

Compensation will be based on experience, technical ability, and location.

Candidates with strong production experience in Linux, Node.js/PM2, NGINX, PostgreSQL, and VoIP infrastructure may qualify for higher compensation.