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After solving the cleaning up process, we landup in another situation and that is weather any of those hosts would come back and if yes how we would know. Should we disable them forever ir should we build up some mechanism to bring them back ? To solve this problem we devised pretty straight forward mechanism i.e. to devise a notification process, which can help us in identifying the landmarks which are up.
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This script performs following actions to identify landmarks being up or down. |
- It pings the host name of the landmark which are disabled
- If the ping is successful it marks the landmark being up
- Else it checks if IP address corresponding to that host is is pingable.
- If IP replies it marks as up and also tells that IP responded
- If ping fails it tries to connect at port, we did this step because there are many hosts which blocks ping requests
- If all the above mentioned steps fail, we mark the host as a not responding.
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If the disabled landmark replies and passes the above mentioned pseudo , we increment the upDays by 1, change value of downDays to 0 and put in the comment that weather the host passed the test or IP was responding. In the same manner if the host fails the test we increment downDays by 1 and mark upDays as 0. With this counter technique at any instant of time we can have an hawk eye view and enable the host if its up for a longer period of time.
An example of the populated table is as follows
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Hosts which are up +-----------------+----------+--------+-----------+ | ipv4Addr | downDays | upDays | comments | +-----------------+----------+--------+-----------+ | 88.255.65.220 | 0 | 1 | OK (name) | | 203.128.4.48 | 0 | 1 | OK (name) | | 203.178.133.11 | 0 | 1 | OK (name) | | 203.178.133.3 | 0 | 1 | OK (name) | | 198.7.242.41 | 0 | 1 | OK (name) | | 198.7.242.42 | 0 | 1 | OK (name) | | 200.133.215.142 | 0 | 1 | OK (name) | +-----------------+----------+--------+-----------+ Hosts which are down +-----------------+----------+-------------+ | ipv4Addr | downDays | comments | +-----------------+----------+-------------+ | 69.110.237.116 | 1 | No Response | | 61.252.60.30 | 1 | No Response | | 216.165.109.82 | 1 | No Response | | 213.131.1.102 | 1 | No Response | | 213.19.160.194 | 1 | No Response | | 216.165.109.79 | 1 | No Response | | 216.165.109.81 | 1 | No Response | | 210.125.84.16 | 1 | No Response | | 212.201.44.81 | 1 | No Response | | 212.201.44.82 | 1 | No Response | | 210.123.39.103 | 1 | No Response | | 128.10.19.53 | 1 | No Response | | 137.138.24.234 | 1 | No Response | +-----------------+----------+-------------+ |
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