I have a solution which measures some values and transmits it in batches when the network is available, so let's say once a day I get measurements for every 5 minutes of the past day. Is there any way that munin can handle this kind of data delivery? Normally, munin fills time slots without information with NULL, so that it's not possible anymore to add this data afterwards. Do I have to manipulate the rrd data myself?
What I'm looking for is inspired by the zabbix active agent
What options do I have to hard-reset a linux driver?
I have a problem with my USB-connected dvb tuners. They crash from time to time with a stack trace in the kernel log and disappear from the device manager. The application (tvheadend, which runs in a docker container) freezes and is not killable anymore, and the docker container can't shutdown, not even being killed.
As all this is connected to an unstable state of the driver, I wonder if it's possible to force-unload or reset it so that I can startup the whole dvb subsystem again without rebooting the machine?
The drivers in my case are si2157 and em28xx*. Unloading using modprobe -r for all dvb-relevant modules fails because the devices are still in use by the frozen process.
I just discovered that service docker stop on Ubuntu 18.04 doesn't shutdown all running containers. I can't control them anymore but the containerd-ship processes and everything that's inside the containers is still running (but not reachable though, maybe because the network was removed).
Also, stopping containerd doesn't change anything because by design this doesn't stop the containers.
And even after killall containerd-shim which is already quite harsh, some processes are still running, like gunicorn from gitlab, backuppc, and a Linux UML instance
How do I do a clean shutdown of all running containers? The current behaviour is responsible that my system hangs while shutting down.
Update: I just saw that I'm using the repo (https://download.docker.com/linux/ubuntu) which comes from a Kubernetes tutorial (which I don't use yet). This source brings proprietary versions of containerd.io, docker-ce and docker-ce-cli
I'm quite new to Kubernetes, event if it doesn't feel like after I spent dozens of hours trying to setup a working Kubernetes.
The edge parameters:
--pod-network-cidr=10.10.0.0/16)Installation using kubeadm init and joining worked so far. All pods are running, only coredns keeps crashing, but this is not relevant here.
Then, I starting with installing with the etcd datastore and installing with the kubernetes api datastore 50 nodes or less
kubectl apply -f https://docs.projectcalico.org/v3.2/getting-started/kubernetes/installation/rbac.yaml
curl https://docs.projectcalico.org/v3.2/getting-started/kubernetes/installation/hosted/calico.yaml -O
# modify calico.yaml # Here, I feel a lack of documentation: Which etcd is needed? The one of kubernetes or a new one? See below
kubectl apply -f calico.yaml
kubectl apply -f https://docs.projectcalico.org/v3.2/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
curl https://docs.projectcalico.org/v3.2/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml -O
# modify calico.yaml (here, I have to change the range of CALICO_IPV4POOL_CIDR)
sed -i 's/192.168.0.0/10.10.0.0/' calico.yaml
kubectl apply -f calico.yaml
Now, I use the following definition for testing:
apiVersion: v1
kind: Pod
metadata:
name: www1
labels:
service: testwww
spec:
containers:
- name: meinserver
image: erkules/nginxhostname
ports:
- containerPort: 80
---
apiVersion: v1
kind: Pod
metadata:
name: www2
labels:
service: testwww
spec:
containers:
- name: meinserver
image: erkules/nginxhostname
---
kind: Service
apiVersion: v1
metadata:
name: www-np
spec:
type: NodePort
selector:
service: testwww
ports:
- name: http1
protocol: TCP
nodePort: 30333
port: 8080
targetPort: 80
How I test:
curl http://192.168.1.211:30333 # master, no success
curl http://192.168.1.212:30333 # node, no success
curl http://192.168.1.213:30333 # node, only works 50%, with www1 (which is on this node)
curl http://192.168.1.214:30333 # node, only works 50%, with www2 (which is on this node)
The above commands work only if the (randomly chosen) pod is on the node which owns the specified IP address. I expected to have 100% success rate on all nodes.
I saw more success when using the etcd server of kubernetes (pod/etcd-master1). In this case, all the above commands worked. But the pod/calico-kube-controllers didn't start in this case because it was running on a worker node and thus didn't have access to etcd.
In the getting started guide, I found an instruction to install an extra etcd:
kubectl apply -f https://docs.projectcalico.org/v3.2/getting-started/kubernetes/installation/hosted/etcd.yaml
It's weird: This line is only in the "getting started", but not in "installation". But the default calico.yaml already contains the correct clusterIp of exactly this etcd server (btw how is this IP static? Is it generated by a hash?). Anyway: with this, all Calico nodes came up without an error, but I had the described behaviour where not all NodePorts were working. And I also care about etcd which is open to everyone this way which is not what I want.
Btw: I was the answers which recommend changing the iptables default rule from DROP to ACCEPT. But this is an ugly hack and probably bypasses all of the security features of Calico
$ kubectl get all --all-namespaces=true -o wide; kubectl get nodes -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default pod/www1 1/1 Running 0 8s 192.168.104.9 node2 <none>
default pod/www2 1/1 Running 0 8s 192.168.166.136 node1 <none>
kube-system pod/calico-etcd-46g2q 1/1 Running 0 22m 192.168.1.211 master1 <none>
kube-system pod/calico-kube-controllers-f4dcbf48b-88795 1/1 Running 10 23h 192.168.1.212 node0 <none>
kube-system pod/calico-node-956lj 2/2 Running 6 21h 192.168.1.213 node1 <none>
kube-system pod/calico-node-mhtvg 2/2 Running 5 21h 192.168.1.211 master1 <none>
kube-system pod/calico-node-s9njn 2/2 Running 6 21h 192.168.1.214 node2 <none>
kube-system pod/calico-node-wjqlk 2/2 Running 6 21h 192.168.1.212 node0 <none>
kube-system pod/coredns-576cbf47c7-4tcx6 0/1 CrashLoopBackOff 15 24h 192.168.137.86 master1 <none>
kube-system pod/coredns-576cbf47c7-hjpgv 0/1 CrashLoopBackOff 15 24h 192.168.137.85 master1 <none>
kube-system pod/etcd-master1 1/1 Running 17 24h 192.168.1.211 master1 <none>
kube-system pod/kube-apiserver-master1 1/1 Running 2 24h 192.168.1.211 master1 <none>
kube-system pod/kube-controller-manager-master1 1/1 Running 3 24h 192.168.1.211 master1 <none>
kube-system pod/kube-proxy-22mb9 1/1 Running 2 23h 192.168.1.212 node0 <none>
kube-system pod/kube-proxy-96tn7 1/1 Running 2 23h 192.168.1.213 node1 <none>
kube-system pod/kube-proxy-vb4pq 1/1 Running 2 24h 192.168.1.211 master1 <none>
kube-system pod/kube-proxy-vq7qj 1/1 Running 2 23h 192.168.1.214 node2 <none>
kube-system pod/kube-scheduler-master1 1/1 Running 2 24h 192.168.1.211 master1 <none>
kube-system pod/kubernetes-dashboard-77fd78f978-h8czs 1/1 Running 2 23h 192.168.180.9 node0 <none>
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
default service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 24h <none>
default service/www-np NodePort 10.99.149.53 <none> 8080:30333/TCP 8s service=testwww
kube-system service/calico-etcd ClusterIP 10.96.232.136 <none> 6666/TCP 21h k8s-app=calico-etcd
kube-system service/calico-typha ClusterIP 10.105.199.162 <none> 5473/TCP 23h k8s-app=calico-typha
kube-system service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 24h k8s-app=kube-dns
kube-system service/kubernetes-dashboard ClusterIP 10.96.235.235 <none> 443/TCP 23h k8s-app=kubernetes-dashboard
NAMESPACE NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE CONTAINERS IMAGES SELECTOR
kube-system daemonset.apps/calico-etcd 1 1 1 1 1 node-role.kubernetes.io/master= 21h calico-etcd quay.io/coreos/etcd:v3.3.9 k8s-app=calico-etcd
kube-system daemonset.apps/calico-node 4 4 4 4 4 beta.kubernetes.io/os=linux 23h calico-node,install-cni quay.io/calico/node:v3.2.3,quay.io/calico/cni:v3.2.3 k8s-app=calico-node
kube-system daemonset.apps/kube-proxy 4 4 4 4 4 <none> 24h kube-proxy k8s.gcr.io/kube-proxy:v1.12.1 k8s-app=kube-proxy
NAMESPACE NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
kube-system deployment.apps/calico-kube-controllers 1 1 1 1 23h calico-kube-controllers quay.io/calico/kube-controllers:v3.2.3 k8s-app=calico-kube-controllers
kube-system deployment.apps/calico-typha 0 0 0 0 23h calico-typha quay.io/calico/typha:v3.2.3 k8s-app=calico-typha
kube-system deployment.apps/coredns 2 2 2 0 24h coredns k8s.gcr.io/coredns:1.2.2 k8s-app=kube-dns
kube-system deployment.apps/kubernetes-dashboard 1 1 1 1 23h kubernetes-dashboard k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.0 k8s-app=kubernetes-dashboard
NAMESPACE NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
kube-system replicaset.apps/calico-kube-controllers-f4dcbf48b 1 1 1 23h calico-kube-controllers quay.io/calico/kube-controllers:v3.2.3 k8s-app=calico-kube-controllers,pod-template-hash=f4dcbf48b
kube-system replicaset.apps/calico-typha-5f646c475c 0 0 0 23h calico-typha quay.io/calico/typha:v3.2.3 k8s-app=calico-typha,pod-template-hash=5f646c475c
kube-system replicaset.apps/coredns-576cbf47c7 2 2 0 24h coredns k8s.gcr.io/coredns:1.2.2 k8s-app=kube-dns,pod-template-hash=576cbf47c7
kube-system replicaset.apps/kubernetes-dashboard-77fd78f978 1 1 1 23h kubernetes-dashboard k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.0 k8s-app=kubernetes-dashboard,pod-template-hash=77fd78f978
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master1 Ready master 24h v1.12.0 192.168.1.211 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node0 Ready <none> 23h v1.12.0 192.168.1.212 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node1 Ready <none> 23h v1.12.0 192.168.1.213 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node2 Ready <none> 23h v1.12.0 192.168.1.214 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
$ for i in $(seq 20); do timeout 1 curl -so/dev/null http://192.168.1.214:30333 && echo -n x || echo -n - ;done
x---x-x-x--x-xx-x---
$ kubectl get all --all-namespaces=true -o wide; kubectl get nodes -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default pod/www1 1/1 Running 0 9m27s 10.10.2.3 node1 <none>
default pod/www2 1/1 Running 0 9m27s 10.10.3.3 node2 <none>
kube-system pod/calico-kube-controllers-f4dcbf48b-qrqnc 0/1 CreateContainerConfigError 1 18m 192.168.1.212 node0 <none>
kube-system pod/calico-node-j8cwr 2/2 Running 2 17m 192.168.1.212 node0 <none>
kube-system pod/calico-node-qtq9m 2/2 Running 2 17m 192.168.1.214 node2 <none>
kube-system pod/calico-node-qvf6w 2/2 Running 2 17m 192.168.1.211 master1 <none>
kube-system pod/calico-node-rdt7k 2/2 Running 2 17m 192.168.1.213 node1 <none>
kube-system pod/coredns-576cbf47c7-6l9wz 1/1 Running 2 21m 10.10.0.11 master1 <none>
kube-system pod/coredns-576cbf47c7-86pxp 1/1 Running 2 21m 10.10.0.10 master1 <none>
kube-system pod/etcd-master1 1/1 Running 19 20m 192.168.1.211 master1 <none>
kube-system pod/kube-apiserver-master1 1/1 Running 2 20m 192.168.1.211 master1 <none>
kube-system pod/kube-controller-manager-master1 1/1 Running 1 20m 192.168.1.211 master1 <none>
kube-system pod/kube-proxy-28qct 1/1 Running 1 20m 192.168.1.212 node0 <none>
kube-system pod/kube-proxy-8ltpd 1/1 Running 1 21m 192.168.1.211 master1 <none>
kube-system pod/kube-proxy-g9wmn 1/1 Running 1 20m 192.168.1.213 node1 <none>
kube-system pod/kube-proxy-qlsxc 1/1 Running 1 20m 192.168.1.214 node2 <none>
kube-system pod/kube-scheduler-master1 1/1 Running 5 19m 192.168.1.211 master1 <none>
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
default service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21m <none>
default service/www-np NodePort 10.106.27.58 <none> 8080:30333/TCP 9m27s service=testwww
kube-system service/calico-typha ClusterIP 10.99.14.62 <none> 5473/TCP 17m k8s-app=calico-typha
kube-system service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 21m k8s-app=kube-dns
NAMESPACE NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE CONTAINERS IMAGES SELECTOR
kube-system daemonset.apps/calico-node 4 4 4 4 4 beta.kubernetes.io/os=linux 18m calico-node,install-cni quay.io/calico/node:v3.2.3,quay.io/calico/cni:v3.2.3 k8s-app=calico-node
kube-system daemonset.apps/kube-proxy 4 4 4 4 4 <none> 21m kube-proxy k8s.gcr.io/kube-proxy:v1.12.1 k8s-app=kube-proxy
NAMESPACE NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
kube-system deployment.apps/calico-kube-controllers 1 1 1 0 18m calico-kube-controllers quay.io/calico/kube-controllers:v3.2.3 k8s-app=calico-kube-controllers
kube-system deployment.apps/calico-typha 0 0 0 0 17m calico-typha quay.io/calico/typha:v3.2.3 k8s-app=calico-typha
kube-system deployment.apps/coredns 2 2 2 2 21m coredns k8s.gcr.io/coredns:1.2.2 k8s-app=kube-dns
NAMESPACE NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
kube-system replicaset.apps/calico-kube-controllers-f4dcbf48b 1 1 0 18m calico-kube-controllers quay.io/calico/kube-controllers:v3.2.3 k8s-app=calico-kube-controllers,pod-template-hash=f4dcbf48b
kube-system replicaset.apps/calico-typha-5f646c475c 0 0 0 17m calico-typha quay.io/calico/typha:v3.2.3 k8s-app=calico-typha,pod-template-hash=5f646c475c
kube-system replicaset.apps/coredns-576cbf47c7 2 2 2 21m coredns k8s.gcr.io/coredns:1.2.2 k8s-app=kube-dns,pod-template-hash=576cbf47c7
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master1 Ready master 21m v1.12.0 192.168.1.211 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node0 Ready <none> 20m v1.12.0 192.168.1.212 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node1 Ready <none> 20m v1.12.0 192.168.1.213 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node2 Ready <none> 20m v1.12.0 192.168.1.214 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
$ for i in $(seq 20); do timeout 1 curl -so/dev/null http://192.168.1.214:30333 && echo -n x || echo -n - ;done
xxxxxxxxxxxxxxxxxxxx
I just tried with flannel: Result is surprisingly the same as with extra etcd (pods only answering if on the same node). This brings me to the question: is there anything about my OS? Ubuntu 18.04 with latest updates, installed using debootstrap. No firewall...
How I installed it:
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Result:
$ kubectl get all --all-namespaces=true -o wide; kubectl get nodes -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default pod/www1 1/1 Running 0 3m40s 10.10.2.2 node1 <none>
default pod/www2 1/1 Running 0 3m40s 10.10.3.2 node2 <none>
kube-system pod/coredns-576cbf47c7-64wxp 1/1 Running 3 21m 10.10.1.3 node0 <none>
kube-system pod/coredns-576cbf47c7-7zvqs 1/1 Running 3 21m 10.10.1.2 node0 <none>
kube-system pod/etcd-master1 1/1 Running 0 21m 192.168.1.211 master1 <none>
kube-system pod/kube-apiserver-master1 1/1 Running 0 20m 192.168.1.211 master1 <none>
kube-system pod/kube-controller-manager-master1 1/1 Running 0 21m 192.168.1.211 master1 <none>
kube-system pod/kube-flannel-ds-amd64-brnmq 1/1 Running 0 8m22s 192.168.1.214 node2 <none>
kube-system pod/kube-flannel-ds-amd64-c6v67 1/1 Running 0 8m22s 192.168.1.213 node1 <none>
kube-system pod/kube-flannel-ds-amd64-gchmv 1/1 Running 0 8m22s 192.168.1.211 master1 <none>
kube-system pod/kube-flannel-ds-amd64-l9mpl 1/1 Running 0 8m22s 192.168.1.212 node0 <none>
kube-system pod/kube-proxy-5pmtc 1/1 Running 0 21m 192.168.1.213 node1 <none>
kube-system pod/kube-proxy-7ctp5 1/1 Running 0 21m 192.168.1.212 node0 <none>
kube-system pod/kube-proxy-9zfhl 1/1 Running 0 21m 192.168.1.214 node2 <none>
kube-system pod/kube-proxy-hcs4g 1/1 Running 0 21m 192.168.1.211 master1 <none>
kube-system pod/kube-scheduler-master1 1/1 Running 0 20m 192.168.1.211 master1 <none>
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
default service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 22m <none>
default service/www-np NodePort 10.101.213.118 <none> 8080:30333/TCP 3m40s service=testwww
kube-system service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 22m k8s-app=kube-dns
NAMESPACE NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE CONTAINERS IMAGES SELECTOR
kube-system daemonset.apps/kube-flannel-ds-amd64 4 4 4 4 4 beta.kubernetes.io/arch=amd64 8m22s kube-flannel quay.io/coreos/flannel:v0.10.0-amd64 app=flannel,tier=node
kube-system daemonset.apps/kube-flannel-ds-arm 0 0 0 0 0 beta.kubernetes.io/arch=arm 8m22s kube-flannel quay.io/coreos/flannel:v0.10.0-arm app=flannel,tier=node
kube-system daemonset.apps/kube-flannel-ds-arm64 0 0 0 0 0 beta.kubernetes.io/arch=arm64 8m22s kube-flannel quay.io/coreos/flannel:v0.10.0-arm64 app=flannel,tier=node
kube-system daemonset.apps/kube-flannel-ds-ppc64le 0 0 0 0 0 beta.kubernetes.io/arch=ppc64le 8m21s kube-flannel quay.io/coreos/flannel:v0.10.0-ppc64le app=flannel,tier=node
kube-system daemonset.apps/kube-flannel-ds-s390x 0 0 0 0 0 beta.kubernetes.io/arch=s390x 8m21s kube-flannel quay.io/coreos/flannel:v0.10.0-s390x app=flannel,tier=node
kube-system daemonset.apps/kube-proxy 4 4 4 4 4 <none> 22m kube-proxy k8s.gcr.io/kube-proxy:v1.12.1 k8s-app=kube-proxy
NAMESPACE NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
kube-system deployment.apps/coredns 2 2 2 2 22m coredns k8s.gcr.io/coredns:1.2.2 k8s-app=kube-dns
NAMESPACE NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
kube-system replicaset.apps/coredns-576cbf47c7 2 2 2 21m coredns k8s.gcr.io/coredns:1.2.2 k8s-app=kube-dns,pod-template-hash=576cbf47c7
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master1 Ready master 22m v1.12.1 192.168.1.211 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node0 Ready <none> 21m v1.12.1 192.168.1.212 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node1 Ready <none> 21m v1.12.1 192.168.1.213 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
node2 Ready <none> 21m v1.12.1 192.168.1.214 <none> Ubuntu 18.04 LTS 4.15.0-20-generic docker://17.12.1-ce
$ for i in $(seq 20); do timeout 1 curl -so/dev/null http://192.168.1.214:30333 && echo -n x || echo -n - ;done
-x--xxxxx-x-x---xxxx
I'm trying to setup a boot server which only answers to devices which want to boot over the network. Depending on the boot rom, I need to deliver different boot images, the other settings are common.
My current configuration (/etc/dhcp/dhcpd.conf) is:
ddns-update-style none;
default-lease-time 60;
max-lease-time 100;
log-facility local7;
class "DM814x ROM" {
match if substring (option vendor-class-identifier, 0, 10) = "DM814x ROM";
filename "u-boot-spl-debrick.bin";
}
class "AM335x U-Boot SPL" {
match if substring (option vendor-class-identifier, 0, 17) = "AM335x U-Boot SPL";
filename "u-boot-debrick.img";
}
# more possible strings: "PXEClient", "Etherboot"
log (error,
concat ("TEST DUMP:"
, " mac=", binary-to-ascii(16, 8, ":", substring(hardware, 1, 6))
, " substr='", substring (option vendor-class-identifier, 0, 10), "'"
, " vendor='", option vendor-class-identifier, "'"
#, " dhcpvendor='", option dhcp-vendor-identifier, "'"
)
);
subnet 10.0.42.0 netmask 255.255.255.0 {
#server-name "10.0.42.1";
#option routers 10.0.42.1;
#option domain-name "example.org";
#option domain-name-servers ns1.example.org, ns2.example.org;
pool {
range 10.0.42.200 10.0.42.240;
allow members of "DM814x ROM";
allow members of "AM335x U-Boot SPL";
#allow dynamic bootp clients;
}
}
Now, it seems that the class is not assigned. I also tried to implement it using subclasses but with the same effect. The log statement showed me that the returned string is correct (and substring() really uses base 0 [which is not documented]).
For some tests I used the allow dynamic bootp clients statement. The result was that the host received an ip address but without the file name which shows that the class was still not assigned.
Recently I configured some passive checks in Zabbix. Now, I saw that some checks failed for some periods of time, but this is not clear when looking at the chart. It seems that the value was stable for the last week but in real performance went down and nobody recognized it.
Is there a way to send NULL to Zabbix to indicate that fetching of the data failed? And to add a trigger for this case? I'm currently using the command line tool zabbix_sender to upload the results, but can change to an alternative.
In contrast, munin stops graphing 10 minutes after receiving the last value and the missing values are also not influencing the calculation of the average value.
Here you can see how the 'missing data' is displayed:
in the chart (I marked the 'missing data'):
in the 'Last data' table (the line is grayed out, but the value 'last check' shows almost the current time)
Btw: the same problems is in the icmppingsec[] check which just returns 0 in case of an error. Not very helpful for graphing but at least this avoids false negatives.
Given the following installation:
old router 192.168.1.1 with NAT forward of tcp port 80 to 192.168.1.10:80
new router 192.168.1.2 with NAT forward of tcp port 80 to 192.168.1.10:80
web server 192.168.1.10 with default gateway 192.168.1.1
Currently, the DNS entry for my service points to the external address of the old router. The router does a port forwarding of the traffic to the web server which returns the answer back to the old gateway.
For a seamless migration to a new router (with another external IP), I want to setup a new router first, test the whole thing with both connections active, and then change the DNS IP to the new external address.
Now, with the above setup, the old router still works. But tcp connections which are addressed to the new router, are also answered to the old router which cannot handle them.
I thought about using nat with masquerading but then all traffic which is addressed to the new router will look like local traffic. This tricks out server ip-based filters and logging.
Now, my plan is to use a helper PC with Debian and iptables for a temporary solution:
old router 192.168.1.1 with NAT forward of tcp port 80 to 192.168.1.10:80
new router 192.168.1.2 with NAT forward of tcp port 80 to 192.168.1.20:80
web server 192.168.1.10 with default gateway 192.168.1.20
helper pc 192.168.1.20
the helper pc is now responsible for finding the correct gateway:
I found a lot of input in the internet and especially serverfault.com (especially this one), but all of them cover only a single part of this problem. I guess it needs a combination of mac address based filter rules -m mac --mac-source <mac>, NAT, states and rt_tables --set-mark / ip rule add fwmark (--gw doesn't seem to be supported by Debian).
When licensing User CALS for Windows Server, I have following problem (or question):
Given you have 30 employees in your domain. 5 of them are administrators. Each of these administrator has two domain accounts, one for working, with almost normal permissions, and one account with domain admin permissions, for logging in into servers and workstations. This helps distinguishing who was responsible for a software installation, reboot etc.
Now, do I need to buy 35 licenses for those 30 physical employees because I have 35 user accounts or is it enough to buy one user CAL per (physical) admin?
Same question appears for a special backup user which is used by backup scripts (=no physical user) to tranfer files to our file pool.
I already checked Active Directory Licensing but it doesn't completely cover my question.