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Below is the deep, real-world view** of how a **strong SRE/DevOps engineer sits inside a multidata center (multi-DC) environment built on:
SRE-DevOps-engineer
* MAAS for bare-metal lifecycle
* Proxmox** for virtualization
* OpenStack for cloud/IaaS
* Dedicated networking (L2/L3/VLAN/BGP/EVPN)
* Automation + Observability spanning all layers
This is the true role in a modern organization operating multiple sites, GPUs, hybrid workloads, and self-service infrastructure.
---
# 🧭 1. **Where the SRE/DevOps Sits in the Architecture**
A strong SRE/DevOps is positioned **between hardware → platform → developers**, as the owner of the **full infrastructure lifecycle**.
```
[ Developers / ML / Platform Teams ]
│ Self-service, APIs, IaC
┌──────────────────────────┐
│ Strong SRE/DevOps Owner │ ◄── Reliability, Automation, Architecture
└──────────────────────────┘
▲ ▲ ▲
│ │ │
[MAAS Bare Metal] [Proxmox] [OpenStack]
[Cluster Setup ] [VM Infra] [Cloud IaaS]
▲ ▲ ▲
└────────────┴─────────────┘
Network / Storage
Physical DC Infrastructure
```
---
# 🧱 2. **The SRE/DevOps owns the entire stack end-to-end**
## **A. Bare-Metal Layer (MAAS / Ironic / PXE)**
The strong SRE/DevOps is responsible for:
* Multi-DC MAAS region/rack-controller architecture
* PXE → Preseed → Cloud-init → config mgmt
* Golden images for Ubuntu (Proxmox/OpenStack nodes)
* RAID configuration, NIC bonding, BIOS/firmware standards
* GPU detection, PCIe topology validation
* Integrating MAAS with CMDB, billing, compute tracking, GPU inventory
**Why critical?**
This defines hardware bootstrap & repeatability. Every DC depends on it.
---
## **B. Virtualization Layer (Proxmox Clusters)**
The SRE/DevOps maintains:
* Multi-node Proxmox clusters per DC
* Shared storage pools (Ceph, ZFS replication, NVMe tiers)
* High availability
* Lifecycle automation for templates, images, API-based VM creation
* Terraform integration
* Networking: bonds, bridges, VLAN tagging, VRRP, routing domains
**Why important?**
Proxmox often hosts internal systems, CI/CD, observability, runners, and even OpenStack control nodes.
---
## **C. Cloud Layer (OpenStack)**
The SRE/DevOps is responsible for:
* Kolla-Ansible lifecycle (deploy, upgrade, rollback)
* Nova, Neutron, Glance, Keystone, Cinder architectures
* Multi-DC regions/availability zones
* Underlay support: L2/L3, MTU, VXLAN, BGP EVPN, DHCP/DNS
* API endpoints, load balancers, certificate rotation
* Quota management, capacity planning
* GPU flavors, PCI passthrough, SR-IOV networks
**Why important?**
OpenStack provides elastic compute + GPU pools for internal workloads.
---
# 🕸️ 3. **SRE/DevOps Responsibilities Across Multi-DC**
## **A. Multi-DC Strategy & Standardization**
Across 310 DCs, the strong SRE/DevOps ensures:
* Consistent **naming conventions**, network CIDRs, VLAN plans
* Identical MAAS rack-controller layout
* Same Proxmox cluster topology
* Same OpenStack region layout
* Unified OS images, configs, automation, observability patterns
* DC-to-DC failover tested and documented
* Common CI/CD pipeline for infra changes
This is architectural leadership.
---
## **B. Networking Integration**
A strong SRE/DevOps is not a network engineer—but understands enough to architect the underlay/overlay needs:
* VLAN allocation for provisioning, storage, tenants
* Spine-leaf fabric requirements (MTU, VTEP placements)
* Routing for MAAS DHCP/TFTP
* BGP, EVPN, VRRP/Keepalived, LACP bundles
* Multicast needs for Ceph or Proxmox clusters
* Tenant isolation (OpenStack Neutron)
You bridge **compute** and **network**, ensuring both work without finger-pointing.
---
## **C. Automation & GitOps Ownership**
Everything from:
* MAAS commissioning
* Proxmox cluster creation
* OpenStack environment provisioning
* Network configs
* Observability stack deployments
…is defined as **IaC** and deployed via:
* GitLab/GitHub Actions
* Terraform
* Ansible
* Python automation libraries
* Event-driven workflows (webhooks, APIs)
The strong SRE turns the entire infrastructure into a **code forest**, not a collection of manual operations.
---
## **D. Reliability Engineering Layer**
Owns:
* SLOs for control plane components
* Prometheus/Grafana dashboards spanning MAAS, hypervisors, OpenStack, networks
* Alerting strategy
* Runbooks + automated remediation
* Incident response framework
* Capacity projections across DCs (CPU/GPU/NVMe/RAM/network)
This is what makes the difference between a *DevOps engineer* and a **strong SRE**.
---
# ⚙️ 4. **How the SRE/DevOps Interacts with Each Layer (Detailed)**
---
# **Layer 1 — Hardware (Bare-metal servers)**
### You ensure:
* consistent hardware standards
* automated testing/commissioning
* BIOS/firmware alignment
* RAID and BMC integration
* DC racks follow a uniform provisioning model
---
# **Layer 2 — MAAS Region Controllers**
### You design:
* Region ↔ Rack hierarchy
* HA for MAAS API
* DHCP/TFTP separation per DC
* Multi-DC image mirrors
* Secure API integration with downstream systems
* Lifecycle automation from “server purchased” → “in production”
---
# **Layer 3 — Proxmox Virtualization**
### You own:
* cluster deployment automation
* storage pools (Ceph, ZFS)
* backup/restore strategy
* VM template pipeline
* Terraform-driven VM creation
* GPU virtualization, passthrough, SR-IOV setups
---
# **Layer 4 — OpenStack Cloud**
### You architect:
* multi-region API
* Keystone federation
* Nova scheduling across DCs and AZs
* Neutron routing domains
* Cinder backends, replication
* Glance image replication
* CI/CD for Kolla upgrades
* Observability for every control plane service
---
# **Layer 5 — Networking Integration**
### You interface deeply with:
* BGP (underlay and overlay)
* EVPN-VXLAN
* VLAN-to-tenant isolation
* Proxmox/MAAS provisioning networks
* OpenStack Neutron overlays
* DC interconnects (L2 extensions, MPLS, routing)
You dont configure all routers—but you design the service topology and requirements.
---
# **Layer 6 — Observability & Operations**
### You build:
* Prometheus federation
* Loki/ELK pipelines
* GPU telemetry exporters
* DC health dashboards
* Error budget reports
* Synthetic probes for OpenStack APIs
* Capacity dashboards (CPU/GPU/storage per DC)
---
# **Layer 7 — Self-service Interfaces**
You provide:
* VM creation portals (via Proxmox API or Terraform Cloud)
* Bare-metal on-demand via MAAS API
* GPU cloud flavors via OpenStack API
* Internal developer services (logging, metrics, backups, secrets)
This is what **developers and ML engineers see**.
---
# 💼 5. **The Mission of a Strong SRE in Multi-DC Environments**
### **You build a unified infrastructure fabric across all DCs.**
Your goals:
✔ Zero manual provisioning
✔ Zero snowflake clusters
✔ Infrastructure reproducible from Git
✔ All DCs behave identically
✔ High availability across regions
✔ Stable, predictable performance for GPU workloads
✔ Automated OS, hypervisor, and control-plane lifecycle
✔ Capacity planning, telemetry, and self-healing
✔ Clear SLIs/SLOs for infra services
✔ Security controls embedded in workflows
This is the **modern definition** of SRE excellence.
---
# 📌 6. One sentence summary
**A strong SRE/DevOps is the architect and owner of the entire infrastructure lifecycle across multi-DC bare-metal, virtualization, cloud, networking, and automation, ensuring everything is reproducible, observable, reliable, and scalable.**
---