This is an old revision of the document!

D

DHCP = Dynamic Host Configuration Protocol
- Used to allocated the internal IP addresses of VMs and services depending on VMs like AppEngine or GKE, with leases renewed every 24 hours
DEK: Data Encryption Key
- In Cloud KMS, a key actually used to encrypt data, not to encrypt other keys
- Compare KEK
Deployment: in Kubernetes, an object for deploying stateless applications like web servers.
- Compare Service
Discovery Document: the specification for a GCP API, similar to OpenAPI but not the same
- https://developers.google.com/discovery/v1/reference/apis
DoQ = DNS over QUIC
- Defined in RFC 9250
DORA = DevOps Research and Assessment
- https://dora.dev/
- a research program, that seeks to understand the capabilities that drive software delivery and operations performance
- mostly known for DORA Metrics, although that name never appears on their site:
  - Deployment Frequency
  - Lead Time for Changes
  - Mean Time to Recover
  - Change Failure Rate
DoS = Denial of Service
DSR = Direct Server Return
- A load balancing mechanism in which inbound packets flow from switch to LB to backend, and response (outbound) ones return to the switch, bypassing the LB. This is possible because the LB modifies the MAC addresses on the inbound packets
- Preserves the source addresses of the clients, unlike proxy-based LB
- In GCP, used by the “External TCP/UDP network load balancer”
- aka Direct Routing, aka nPath Routing
- How DSR works
- Invented by IBM in the 90s. Minimizes LB load since the return packets do not traverse it.
- Included in the Linux kernel as IPVS (part of LVS) since 2.4
Durability: a measurement related to data protection
- See RPO, RTO