When using the BGP module in Free Range Routing, the 'network The draw back to advertising connected prefixes is that the prefix is advertised even a related interface is not 'up'. This could lead to a blackhole scenario.
A better way to handle the advertisements of connected prefixes is to use the 'redistribute connected' command.
Even with the use of this command, there may be scenarios (which I need to test at some point) where the prefix is advertised or withdrawn depending upon the link state. Free Range Routing has an additional command which could be used to ensure link state checking: 'bgp network import-check'.
There is more about the Linux state checking flags in the
Why Link-State Matters presentation from LinuxCon 2015.
In addition, the Free Range Routing developers have brought together some
relevant sysctl settings.
Monday, April 30. 2018
Linux Link State and Free Range Routing
Linux Drive Access
When a drive has lots of activity for seemingly no reason, what tools are available to troubleshoot? Here are a few possibilities.
Debian provides a tool called iotop, via the package iotop, which, by default, provides a 'top'-like experience. A different command line experience can be achieved through something like (which every 10secs prints a list of processes that read/wrote to disk and the amount of IO bandwidth used):
# iotop -o -b -d 10 Total DISK READ : 0.00 B/s | Total DISK WRITE : 0.00 B/s Actual DISK READ: 0.00 B/s | Actual DISK WRITE: 0.00 B/s TID PRIO USER DISK READ DISK WRITE SWAPIN IO COMMAND Total DISK READ : 0.00 B/s | Total DISK WRITE : 2041.86 B/s Actual DISK READ: 0.00 B/s | Actual DISK WRITE: 1837.68 B/s TID PRIO USER DISK READ DISK WRITE SWAPIN IO COMMAND 19967 be/4 root 0.00 B/s 2041.86 B/s 0.00 % 0.00 % conntrackd -C /etc/conntrackd/conntrackd.conf 14023 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % perl /usr/sbin/x2gocleansessions
More use cases are available at How to find which process is regularly writing to disk?
General statistics, which could be coupled with a 'wait', or in this case it refreshes itself with -k:
Continue reading "Linux Drive Access" »# iostat -xk 2 /dev/sdb Linux 4.14.0-0.bpo.3-amd64 (host01.ny1) 05/26/18 _x86_64_ (16 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 0.31 0.00 0.66 0.09 0.00 98.94 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sdb 0.00 1.78 0.24 6.80 98.41 432.03 150.76 0.60 85.97 114.91 84.95 2.13 1.50
Network Operations Industry Trends
Based upon the Call for Proposals for ONS Europe 2018 to be held in Amsterdam in September 2018, this is what the industry appears to be thinking about:
- Networking Latest Trends
- Disaggregation of the Data Plane – Programmable Open Hardware including Silicon & White Boxes + Open Forwarding Innovations/Interfaces
- The Latest in Standards and Open Source Interworking to Drive Industry Forward
- Artificial Intelligence, Machine Learning, and Deep Learning Applied to Networking
- SD-WAN, IIOT, Data Insights, Business Intelligence
- Cloud Native, Kubernetes, and Network Automation
- Containers, Microservices, and the Service Mesh
- Networking Business and Operations
- High Availability, Scalability, Security in Network Platforms
- Next Generation Automated Architecture (Enterprise, Carriers, Cloud)
- Business Case & ROI on Transformation, Next Gen Services Based on SDN/NFV
- Lessons Learned from Migrating/Integrating Legacy PNF/VNF/OSS/BSS to Automated Systems
- Migration of Data Center to Virtualized Software Defined Lessons and Roadmaps
- The Road to 5G deployment; POCs, Pilots, Partners, and Roll-out
- (Technical) Service Provider & Cloud Networking
- Policy, Closed Loop Automation, and Zero Touch
- Edge Computing; Requirements, Tools, and Emerging Solutions
- NFV Security
- Building High Availability in SDN/NFV Solutions
- 5G Application Use Cases; What Comes First?
- The Shift to Microservice-based VNFs
- Multi-Cloud, and the Benefits it Brings
- (Business & Architecture) Service Provider & Cloud Networking
- SDN/NFV Learnings to Date, ROI, TCO, Agility Gains, etc.
- Business Case and Strategy for 5G Workloads; IoT, VR/AR, Connected Cars, etc.
- Software Defined Packet Optical
- Mobile Edge Computing/4G Video/CDN
- Planning the Migration – Legacy Workload Migration, and Integration of New Systems with Existing Carrier OSS/BSS/FCAPS Systems
- (Technical) Enterprise IT DevOps
- Software Defined Data Center Learnings
- Cloud Networking, End to End Solution Stacks – Hypervisor or Container Based
- Container Networking and the Shift to Microservices
- Scale and Performance in SDN Deployments
- Cloud Native App Development
- (Business & Architecture) Enterprise IT (CXO/IT Architects)
- Digital Transformation – Best Practices
- Bringing DevOps to NetOps – Best Practices
- SDN, and Open Networking Case Studies; ROI, TCO, Operations Improvements, etc.
- Intent-Based Networking
- NFV for Enterprise (vE-CPE, etc.)
- Security – Evolving attack surfaces, agile attack counter-measures, etc.
- Industrial IoT, and the Smart Enterprise, Networking’s role